Spatial clustering of livestock Anthrax events associated with agro-ecological zones in Kenya, 1957-2017.

BACKGROUND: Developing disease risk maps for priority endemic and episodic diseases is becoming increasingly important for more effective disease management, particularly in resource limited countries. For endemic and easily diagnosed diseases such as anthrax, using historical data to identify hotspots and start to define ecological risk factors of its occurrence is a plausible approach. Using 666 livestock anthrax events reported in Kenya over 60 years (1957-2017), we determined the temporal and spatial patterns of the disease as a step towards identifying and characterizing anthrax hotspots in the region. METHODS: Data were initially aggregated by administrative unit and later analyzed by agro-ecological zones (AEZ) to reveal anthrax spatio-temporal trends and patterns. Variations in the occurrence of anthrax events were estimated by fitting Poisson generalized linear mixed-effects models to the data with AEZs and calendar months as fixed effects and sub-counties as random effects. RESULTS: The country reported approximately 10 anthrax events annually, with the number increasing to as many as 50 annually by the year 2005. Spatial classification of the events in eight counties that reported the highest numbers revealed spatial clustering in certain administrative sub-counties, with 12% of the sub-counties responsible for over 30% of anthrax events, whereas 36% did not report any anthrax disease over the 60-year period. When segregated by AEZs, there was significantly greater risk of anthrax disease occurring in agro-alpine, high, and medium potential AEZs when compared to the agriculturally low potential arid and semi-arid AEZs of the country (p < 0.05). Interestingly, cattle were > 10 times more likely to be infected by B. anthracis than sheep, goats, or camels. There was lower risk of anthrax events in August (P = 0.034) and December (P = 0.061), months that follow long and short rain periods, respectively. CONCLUSION: Taken together, these findings suggest existence of certain geographic, ecological, and demographic risk factors that promote B. anthracis persistence and trasmission in the disease hotspots.

Depression, injecting drug use, and risky sexual behavior syndemic among women who inject drugs in Kenya: a cross-sectional survey.

BACKGROUND: Injecting drug use (IDU) is a key driver of the HIV epidemic particularly when individuals experience psychosocial conditions and risky sexual behavior in a syndemic manner. This study sets out to assess evidence of a syndemic pattern of psychosocial conditions (IDU, depression, intimate partner violence (IPV)) on one the hand and risky sexual behavior on the other while accounting for the socio-economic disadvantage among women who inject drugs (WWID) in low-income urban settings in Kenya. METHODS: Using a cross-sectional study design, this study recruited 306 WWIDs from two sites in Nairobi between January 2017 and July 2017. Multiple methodologies including descriptive analyses of co-occurrences of psychosocial conditions at the individual level, standard logistic regression analyses to examine relationships and interactions within and between psychosocial conditions and risky sexual behavior, and classification trees algorithm for predictive modeling via machine learning were employed. RESULTS: The prevalence of the psychosocial conditions was as follows: IDU, 88%; depression, 77.1%; and IPV, 84%. The prevalence of risky sexual behavior was 69.3%. IDU and depression were related to each other (P < 0.05) and each of them with risky sexual behavior (P < 0.05). The highest 2-way and 3-way co-occurrence of conditions were reported in IDU and depression (72%) and in IDU, depression, and risky sexual behavior (62%), respectively, indicating clustering of the conditions at the individual level. Further, each additional psychosocial condition (IDU and depression) was associated with sixfold odds (P = 0.000) of having risky sexual behavior suggesting a dose-response relationship. Logistic regression analyses incorporating multiplicative interactive effects returned three significant variables (P < 0.05): IDU*depression interaction effect, "Age when delivered the first child," and "Income." Classification tree modeling represented a 5-level interaction analysis with IDU and depression predicted to have the highest influence on risky sexual behavior. CONCLUSION: Findings provide possible evidence of a syndemic pattern involving IDU, depression, and risky sexual behavior suggesting the need for an integrated approach to the implementation of harm reduction interventions among WWID in low-income urban settings in Kenya. This work highlights the need for further studies to authenticate the findings and to characterize pathways in the syndemic development in WWID.

Temporal variation in confirmed diagnosis of fever-related malarial cases among children under-5 years by community health workers and in health facilities between years 2013 and 2015 in Siaya County, Kenya.

BACKGROUND: Malaria case management continues to experience dynamic changes. Building community capacity is instrumental in both prevention and treatment of malaria. The World Health Organization (WHO) recommends utilization of well-trained and supervised community health workers (CHWs) to reduce the burden of malaria deaths among children under-5 years of age in Africa. Longitudinally-tracked information on utilization of CHWs by communities in terms of trends in diagnosis of malaria in children under-5 years of age is essential in influencing national and local malaria control policies and strategies. METHODS: A desktop review was carried out of a database consisting of confirmed uncomplicated malaria cases in 10 villages using CHWs and out-patient departments of 10 health facilities in children under-five for the period of 3 years between January 2013 and December 2015. Analyses of association between the diagnosed cases and satellite-based rainfall, village and time (months and years) were carried out using a Poisson regression model. RESULTS: Analysis of malaria diagnoses made by CHWs showed the following trends: (i) the incidence of reported documented malaria-positive fever cases increased with time (2013-2015) and the difference over the years was statistically significant (P < 0.001), (ii) specific village was significantly associated (P < 0.001) with reporting malaria-positive fever cases, (iii) the long-term monthly sequence starting from highest to lowest incidence of reported malaria-positive fever cases was July, May and June, March, August, April, September, November, and February, October and, finally, January, and the difference in reported malaria-positives between the months was statistically significant (P = 0.001) and (iv) none of the tested rainfall regimes (current, lagged or cumulative) was associated with reported malaria-positive fever cases during the 3-year period (P > 0.1). Looking at the number of diagnoses made at the health facilities, (i) The number of reported malaria-positive fever cases decreased with time (2013-2015) and the difference among the years was not statistically significant (P = 0.399), (ii) The long-term monthly sequence starting from highest to lowest number of reported malaria-positive fever cases was July, June, May, April, January, August, March, February, September, November, October and December, and the difference between the months was statistically significant (P < 0.001). CONCLUSIONS: CHWs have the potential to play a major role in diagnosing and treating malaria, thereby decreasing under-five children mortality. Temporally, the risk of diagnosing malaria seems predictable and this may present opportunities for policy-targeted malaria preparedness and control. The findings are expected to support policy actions that may scale-up community health services in remote rural settings.

Sero-epidemiology of Peste des petits ruminants virus infection in Turkana County, Kenya.

BACKGROUND: Peste des petits ruminants (PPR) is a contagious viral disease of small ruminants. Serum samples from sheep (n = 431) and goats (n = 538) of all ages were collected in a cross-sectional study in Turkana County, Kenya. The objective was to estimate the sero-prevalence of PPR virus (PPRV) infection and associated risk factors in both species. PPRV competitive enzyme-linked immuno-sorbent assay (c-ELISA) analysed the presence of antibodies in the samples. All analyses were conducted for each species separately. Multivariable logistic regression models were fitted to the data to assess the relationship between the risk factors and PPRV sero-positivity. Mixed-effect models using an administrative sub-location as a random effect were also fitted to adjust for possible clustering of PPRV sero-positivity. Intra-cluster correlation coefficients (ρ) that described the degree of similarity among sero-positive responses for each species in each of the six administrative divisions were estimated. RESULTS: Goats had a significantly higher sero-prevalence of 40% [95% confidence interval (CI): 36%, 44%] compared to sheep with 32% [95% CI: 27%, 36%] (P = 0.008). Combined sero-prevalence estimates were heterogeneous across administrative divisions (n = 6) (range 22% to 65%) and even more across sub-locations (n = 46) (range 0% to 78%). Assuming that PPRV antibodies are protective of infection, a large pool of PPRV susceptible middle age group (>6 months and < 24 months) in both species was estimated. This was based on the low sero-prevalence in this group in goats (14% [95% CI: 10%, 20%]) and in sheep (18% [95% CI: 13%, 25%]). Regression analysis returned significant risk factors across species: in sheep - vaccination status, age and administrative division; in goats - sex, age, administrative division and sex*age interaction. The intra-sub-location correlation coefficients varied widely across divisions (range <0.001 to 0.42) and across species within divisions. CONCLUSIONS: Biological, spatial and socio-ecological factors are hypothesized as possible explanations for variation in PPRV sero-positivity in the Turkana pastoral ecosystem.

Theileria parva infection seroprevalence and associated risk factors in cattle in Machakos County, Kenya.

The principle objective of this study was to estimate the infection seroprevalence and identify risk factors associated with Theileria parva infection in cattle on smallholder farms in Machakos County, Kenya. A total of 127 farms were selected by a proportional allocation approach based on the number of farms in four divisions in the county previously selected by stratified random sampling method. Subsequently, a total sample of 421 individual animals was randomly selected from the farms. Information on animal and relevant individual farm management practices was gathered using a standardized questionnaire. Prevalence of serum antibodies was determined using the enzyme-linked immunosorbent assay (ELISA). Multivariable logistic models incorporating random effects at the farm level evaluated the association between the presence of T. parva antibodies and the identified risk variables. The overall estimation of T. parva antibodies in the county was 40.9% (95% confidence interval of 36.1, 45.7%). Seroprevalence to T. parva was significantly associated with animal age, vector tick infestation in the animal, tick control frequency, and administrative division. Further analyses suggested a confounding relationship between administrative division and both breed and grazing system and the T. parva seropositivity. Random effects model yielded intra-farm correlation coefficient (ICC) of 0.18. The inclusion of farm random effect provided a substantially better fit than the standard logistic regression (P = 0.032). The results demonstrate substantial variability in the T. parva infection prevalence within all categories of the cattle population of Machakos County of Kenya, where East Coast fever is endemic.

Global burden of HIV among long-distance truck drivers: a systematic review and meta-analysis.

OBJECTIVES: The purpose of this study was to systematically summarise the empirical evidence on the prevalence of HIV among long-distance truck drivers (LDTDs) from all parts of the world. DESIGN: A systematic review and meta-analysis were conducted. DATA SOURCES: We searched PubMed, ProQuest Central, PubMed Central, Cumulated Index to Nursing and Allied Health Literature and Global Index Medicus to identify relevant information published from 1989 to 16 May 2023. ELIGIBILITY CRITERIA: Peer-reviewed publications of English language reporting on the prevalence of HIV among LDTDs were included. Non-empirical studies like literature reviews were excluded. DATA EXTRACTION AND SYNTHESIS: Using a standardised data abstraction form, we extracted information on study characteristics and HIV prevalence levels. Crude prevalence estimates per 100 participants were computed and later transformed using logit transformation to have them follow a normal distribution. A meta-analysis of prevalences using the random effects model was performed. The I2 statistic was used to quantify the degree of heterogeneity across studies. A subgroup analysis using meta-regression was performed to investigate factors that could explain variability across studies. The Joanna Briggs Institute tools and Newcastle-Ottawa Scale were used to assess the quality of the included studies. To assess the certainty of evidence, the Grading of Recommendations Assessment, Development, and Evaluation approach was used. RESULTS: Of the 1787 articles identified, 42 were included. Most of the included studies were conducted in sub-Saharan Africa (45.23%, n=19) and Asia and the Pacific (35.71%, n=15). The pooled prevalence of HIV was 3.86%, 95% CI (2.22% to 6.64%). The burden of HIV was highest in sub-Saharan Africa at 14.34%, 95% CI (9.94% to 20.26%), followed by Asia and the Pacific at 2.12%, 95 CI (0.94% to 4.7%) and lastly Western, Central Europe and North America at 0.17%, 95% CI (0.03% to 0.82%). The overall heterogeneity score was (I2=98.2%, p<0.001). CONCLUSION: The global burden of HIV among LDTDs is 3.86%, six times higher than that of the general population globally. Compared with other regions, the burden of HIV is highest in sub-Saharan Africa at 14.34%, where it is estimated to be 3% in the general population. Thus, LDTDs endure a disproportionately high burden of HIV compared with other populations. Consequently, more LDTD-centred HIV research and surveillance is needed at national and regional levels to institute tailored preventive policies and interventions. PROSPERO REGISTRATION NUMBER: CRD42023429390.

Higher livestock abortion burden in arid and semi-arid lands, Kenya, 2019-2020.

Tracking livestock abortion patterns over time and across factors such as species and agroecological zones (AEZs) could inform policies to mitigate disease emergence, zoonoses risk, and reproductive losses. We conducted a year-long population-based active surveillance of livestock abortion between 2019 and 2020, in administrative areas covering 52% of Kenya's landmass and home to 50% of Kenya's livestock. Surveillance sites were randomly selected to represent all AEZs in the country. Local animal health practitioners electronically transmitted weekly abortion reports from each ward, the smallest administrative unit, to a central server, using a simple short messaging service (SMS). Data were analyzed descriptively by administrative unit, species, and AEZ to reveal spatiotemporal patterns and relationships with rainfall and temperature. Of 23,766 abortions reported in all livestock species, sheep and goats contributed 77%, with goats alone contributing 53%. Seventy-seven per cent (n = 18,280) of these abortions occurred in arid and semi-arid lands (ASALs) that primarily practice pastoralism production systems. While spatiotemporal clustering of cases was observed in May-July 2019 in the ASALs, there was a substantial seasonal fluctuation across AEZs. Kenya experiences high livestock abortion rates, most of which go unreported. We recommend further research to document the national true burden of abortions. In ASALs, studies linking pathogen, climate, and environmental surveillance are needed to assign livestock abortions to infectious or non-infectious aetiologies and conducting human acute febrile illnesses surveillance to detect any links with the abortions.

Comparative prevalence of diarrheagenic Escherichia coli between children below five years with close contact to food animals in Kisumu County, Kenya.

Introduction: diarrheal infections in young children below five years and food animals are caused by diarrheagenic Escherichia coli strains. The study focused on understanding the association between DEC pathotypes in children below five years and food animals to establish the possibility of zoonotic transmission. Methods: samples from 150 children who presented with diarrhea at the Kisumu County Hospital and 100 stool samples from food animals were collected and processed using culture methods. Molecular identification of the pathotypes was assayed using a primer-specific polymerase chain reaction that targeted the six virulence genes related to the diarrheagenic Escherichia coli pathotypes. Results: one hundred and fifty-six study subjects (100 children samples and 56 food animals) samples were positive for E. coli polymerase chain reaction detection revealed a prevalence of (23%) among children below five years and a prevalence of (20%) among the food animals. Children samples showed Enteroaggregative Escherichia coli, having high phenotypic frequency of (12%) followed by Enterotoxigenic Escherichia coli, (5.3%) and Enteropathogenic Escherichia (3.3%) the least being mixed infections Enteroaggregative/Enterotoxigenic Escherichia coli and Enteroaggregative/Enteropathogenic Escherichia coli with (1.3%) respectively. The food animals found in children homesteads were detected to harbor pathogenic strains of E. coli. Enteropathogenic Escherichia coli was the most prevalent pathotypes detected in cattle (13%) followed by Enterotoxigenic Escherichia coli detected in goats at (4%) and poultry at (3%). Conclusion: presence of diarrheagenic Escherichia coli in food animals could serve as reservoirs of transmitting these bacteria to children below five years.

Community preferred drug delivery approaches for pilot roll-out of a potential novel paediatric schistosomiasis treatment option in two endemic counties of Kenya: A mixed methods study.

Treating preschool age children (PSAC) for schistosomiasis has remained a challenge due to lack of a pediatric formulation. In response to this unmet need, the Paediatric Praziquantel Consortium has developed a potential novel paediatric treatment option. In advance to its roll-out to follow regulatory response, we conducted a social science study to gather information on preferred drug delivery approaches to inform implementation. A cross-sectional study was conducted in eight villages in two purposively selected Kenyan counties. A questionnaire was administered on 690 parents/guardians of PSAC at household level. Preferred drug delivery approaches were analyzed using frequencies and proportions. We conducted key informant interviews with 17 opinion leaders and 28 healthcare workers, and 12 focus group discussions with parents/guardians of PSAC and 7 with community health volunteers (CHVs). Thematic analysis was performed on the qualitative data. Majority of the 690 respondents were women 594 (86.1%) with a mean age of 34.1 (SD = 11.3, min-max = 18-86). Community-based mass drug administration (cMDA) was the most preferred drug delivery method by 598 participants (86.7%), followed by health facility/fixed points by 398 participants (57.7%). Similarly, in the qualitative data participants indicated they prefer cMDA since the CHVs who would distribute the medication are familiar with households with PSAC and are trusted to explain the drug effects. Health facilities/fixed points were the second most preferred drug delivery approach, but some health workers we interviewed expressed concern about potential understaffing and overcrowding of facilities. Appropriate timing of the drug distribution, not to interfere with farming activities, was considered critical, irrespective of the approach used. All profiles of study participants preferred cMDA over the other delivery approaches due to the convenience of receiving drugs at home and providing explanations about the new drug. For positive outcomes, adequate planning, proper timings and community involvement are highly recommended.

Widening geographic range of Rift Valley fever disease clusters associated with climate change in East Africa.

Background: Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterizing recent RVF disease events in East Africa. Methods: Data on 100 disease events (2008 - 2022) from Kenya, Uganda, and Tanzania were obtained from public databases and institutions, and modeled against possible geo-ecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalized difference vegetation index (NDVI), livestock production system, land-use change, and long-term climatic variations. Decadal climatic variations between 1980-2022 were evaluated for association with the changing disease pattern. Results: Of 100 events, 91% were small RVF clusters with a median of one human (IQR, 1-3) and 3 livestock cases (IQR, 2-7). These clusters exhibited minimal human mortality (IQR 0-1), and occurred primarily in highlands (67%), with 35% reported in areas that had never reported RVF disease. Multivariate regression analysis of geo-ecological variables showed a positive correlation between occurrence and increasing temperature and rainfall. A 1oC increase in temperature and 1-unit increase in NDVI, 1-3 months prior were associated with increased RVF incidence rate ratios (IRR) of 1.20 (95% CI 1.1,1.2) and 9.88 (95% CI 0.85, 119.52), respectively. Long-term climatic trends showed significant decadal increase in annual mean temperature (0.12 to 0.3oC/decade, P<0.05), associated with decreasing rainfall in arid and semi-arid lowlands but increasing rainfall trends in highlands (P<0.05). These hotter and wetter highlands showed increasing frequency of RVF clusters, accounting for 76% and 43% in Uganda and Kenya, respectively. Conclusion: These findings demonstrate the changing epidemiology of RVF disease. The widening geographic range of disease is associated with climatic variations, with the likely impact of wider dispersal of virus to new areas of endemicity and future epidemics. Key questions: What is already known on this topic?: Rift Valley fever is recognized for its association with heavy rainfall, flooding, and El Niño rains in the East African region. A growing body of recent studies has highlighted a shifting landscape of the disease, marked by an expanding geographic range and an increasing number of small RVF clusters.What this study adds: This study challenges previous beliefs about RVF, revealing that it predominantly occurs in small clusters rather than large outbreaks, and its association with El Niño is not as pronounced as previously thought. Over 65% of these clusters are concentrated in the highlands of Kenya and Uganda, with 35% occurring in previously unaffected regions, accompanied by an increase in temperature and total rainfall between 1980 and 2022, along with a rise in the annual number of rainy days. Notably, the observed rainfall increases are particularly significant during the short-rains season (October-December), aligning with a secondary peak in RVF incidence. In contrast, the lowlands of East Africa, where typical RVF epidemics occur, display smaller and more varied trends in annual rainfall.How this study might affect research, practice, or policy: The worldwide consequence of the expanding RVF cluster is the broader dispersion of the virus, leading to the establishment of new regions with virus endemicity. This escalation heightens the risk of more extensive extreme-weather-associated RVF epidemics in the future. Global public health institutions must persist in developing preparedness and response strategies for such scenarios. This involves the creation and approval of human RVF vaccines and therapeutics, coupled with a rapid distribution plan through regional banks.

Widening geographic range of Rift Valley fever disease clusters associated with climate change in East Africa.

BACKGROUND: Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterising recent RVF disease events in East Africa. METHODS: Data on 100 disease events (2008-2022) from Kenya, Uganda and Tanzania were obtained from public databases and institutions, and modelled against possible geoecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalised difference vegetation index (NDVI), livestock production system, land-use change and long-term climatic variations. Decadal climatic variations between 1980 and 2022 were evaluated for association with the changing disease pattern. RESULTS: Of 100 events, 91% were small RVF clusters with a median of one human (IQR, 1-3) and three livestock cases (IQR, 2-7). These clusters exhibited minimal human mortality (IQR, 0-1), and occurred primarily in highlands (67%), with 35% reported in areas that had never reported RVF disease. Multivariate regression analysis of geoecological variables showed a positive correlation between occurrence and increasing temperature and rainfall. A 1°C increase in temperature and a 1-unit increase in NDVI, one months prior were associated with increased RVF incidence rate ratios of 1.20 (95% CI 1.1, 1.2) and 1.93 (95% CI 1.01, 3.71), respectively. Long-term climatic trends showed a significant decadal increase in annual mean temperature (0.12-0.3°C/decade, p<0.05), associated with decreasing rainfall in arid and semi-arid lowlands but increasing rainfall trends in highlands (p<0.05). These hotter and wetter highlands showed increasing frequency of RVF clusters, accounting for 76% and 43% in Uganda and Kenya, respectively. CONCLUSION: These findings demonstrate the changing epidemiology of RVF disease. The widening geographic range of disease is associated with climatic variations, with the likely impact of wider dispersal of virus to new areas of endemicity and future epidemics.

Traditional remedies and other characteristics among human snakebite survivors in Baringo county, Kenya, 2010-2020: a case series.

BACKGROUND: Seeking traditional remedies following snakebites leads to avoidable deaths in rural settings in developing countries. METHODS: In this case series study, we identified and recruited 169 snakebite survivors in Baringo county, a hard-to-reach region in northwestern Kenya, who experienced snakebites from 2010 to 2020 using a snowballing technique. We explored associations between traditional and hospital care in managing snakebites and other characteristics. χ2 tests assessed these categorical differences. RESULTS: Fifty-four (33%) of the survivors used traditional remedies to manage snakebites. The majority (56%) were men and aged >18 y (72%); 59% had low education levels and income. They sourced water from rivers or lakes (93%) and used charcoal as an energy source (74%). These survivors (>67%) resided in households practicing free-range and stall-feeding animal husbandry systems and in houses with thatch roofing or an earthen floor structure. Also, >62% reported muscle tremors, fever and chills, while 80% visited health facilities for further treatment. CONCLUSION: Community sensitization covering the risks of non-effective remedies and escalation of training to traditional healers could improve the speed of referrals in hard-to-reach snakebite hotspots. Medical anthropology studies could explore the enablers of continued use of traditional remedies in snakebite management in rural communities.

Spatial distribution of sexual network locations used by long-distance truck drivers along the Northern Corridor highway, Kenya.

BACKGROUND: In Kenya, long-distance truck drivers (LDTDs) using the Northern Corridor highway have a high prevalence of HIV and other sexually transmitted infections (STIs) due to their risky sexual networks. However, the spatial distribution of the sexual network locations used by LDTDs is not well understood. Consequently, healthcare stakeholders have found it difficult to provide spatially targeted HIV/STI interventions among LDTDs. Thus, the study sought to establish the spatial distribution of sexual network locations used by LDTDs along the Northern Corridor highway, to inform efficient distribution and use of limited HIV/STI-prevention resources. METHODS: A cross-sectional study design was used. The study adopted a systematic sampling technique. 296 LDTDs were interviewed using interviewer-administered questionnaires at the Mlolongo weighbridge in Kenya. The LDTDs listed their history of sexual interactions and highway stopovers used during the week preceding data collection. Geospatial modelling techniques, using R statistical software packages for spatial mapping, were employed. Shapefiles were created and overlaid over a map of Kenya using R statistical software to create maps of sexual networks. RESULTS: Forty-two highway stopovers used by LDTDs were spatially distributed along the highway, from the Kenya coast to the Kenya-Uganda border. In general, LDTDs' sexual network hotspots were restricted to the outskirts of major cities along the Northern Corridor highway (Nairobi, Mombasa and Nakuru) as well as the Kenya-Uganda international border. CONCLUSIONS: On the Northern Corridor highway, stopovers situated proximal to major urban areas, as well as those at international border points, frequently serve as sexual network hotspots among LDTDs and their sexual partners. Thus, healthcare stakeholders should improve access to HIV/STI-prevention services targeted for LDTDs at the sexual network hotspots identified in this study.

Optimal control and cost-effectiveness analysis for leptospirosis epidemic.

This paper aims to apply an optimal control theory for the autonomous model of the leptospirosis epidemic to examine the effect of four time-dependent control measures on the model dynamics with cost-effectiveness. Pontryagin's Maximum Principle was used to derive the optimality system associated with the optimal control problem. Numerical simulations of the optimality system were performed for different control strategies and the results were presented graphically with and without controls. The optimality system was simulated using the Forward-Backward Sweep method in the Matlab programme. The numerical results revealed that the combination of all optimal control measures is the most effective strategy for minimizing the spread and impact of disease in the community. Furthermore, a cost-effectiveness analysis was performed to determine the most cost-effective strategy using the incremental cost-effectiveness ratio approach and we observed that the rodenticide control-only strategy is most effective to combat the spread of disease when available resources are limited.

Mapping of cholera hotspots in Kenya using epidemiologic and water, sanitation, and hygiene (WASH) indicators as part of Kenya's new 2022-2030 cholera elimination plan.

Cholera is an issue of major public health importance. It was first reported in Kenya in 1971, with the country experiencing outbreaks through the years, most recently in 2021. Factors associated with the outbreaks in Kenya include open defecation, population growth with inadequate expansion of safe drinking water and sanitation infrastructure, population movement from neighboring countries, crowded settings such as refugee camps coupled with massive displacement of persons, mass gathering events, and changes in rainfall patterns. The Ministry of Health, together with other ministries and partners, revised the national cholera control plan to a multisectoral cholera elimination plan that is aligned with the Global Roadmap for Ending Cholera. One of the key features in the revised plan is the identification of hotspots. The hotspot identification exercise followed guidance and tools provided by the Global Task Force on Cholera Control (GTFCC). Two epidemiological indicators were used to identify the sub-counties with the highest cholera burden: incidence per population and persistence. Additionally, two indicators were used to identify sub-counties with poor WASH coverage due to low proportions of households accessing improved water sources and improved sanitation facilities. The country reported over 25,000 cholera cases between 2015 and 2019. Of 290 sub-counties, 25 (8.6%) sub-counties were identified as a high epidemiological priority; 78 (26.9%) sub-counties were identified as high WASH priority; and 30 (10.3%) sub-counties were considered high priority based on a combination of epidemiological and WASH indicators. About 10% of the Kenyan population (4.89 million) is living in these 30-combination high-priority sub-counties. The novel method used to identify cholera hotspots in Kenya provides useful information to better target interventions in smaller geographical areas given resource constraints. Kenya plans to deploy oral cholera vaccines in addition to WASH interventions to the populations living in cholera hotspots as it targets cholera elimination by 2030.

Mapping brucellosis risk in Kenya and its implications for control strategies in sub-Saharan Africa.

In Sub-Saharan Africa (SSA), effective brucellosis control is limited, in part, by the lack of long-term commitments by governments to control the disease and the absence of reliable national human and livestock population-based data to inform policies. Therefore, we conducted a study to establish the national prevalence and develop a risk map for Brucella spp. in cattle to contribute to plans to eliminate the disease in Kenya by the year 2040. We randomly generated 268 geolocations and distributed them across Kenya, proportionate to the area of each of the five agroecological zones and the associated cattle population. Cattle herds closest to each selected geolocation were identified for sampling. Up to 25 cattle were sampled per geolocation and a semi-structured questionnaire was administered to their owners. We tested 6,593 cattle samples for Brucella immunoglobulin G (IgG) antibodies using an Enzyme-linked immunosorbent assay (ELISA). We assessed potential risk factors and performed spatial analyses and prevalence mapping using approximate Bayesian inference implemented via the integrated nested Laplace approximation (INLA) method. The national Brucella spp. prevalence was 6.8% (95% CI: 6.2-7.4%). Exposure levels varied significantly between agro-ecological zones, with a high of 8.5% in the very arid zone with the lowest agricultural potential relative to a low of 0.0% in the agro-alpine zone with the highest agricultural potential. Additionally, seroprevalence increased with herd size, and the odds of seropositivity were significantly higher for females and adult animals than for males or calves. Similarly, animals with a history of abortion, or with multiple reproductive syndromes had higher seropositivity than those without. At the herd level, the risk of Brucella spp. transmission was higher in larger herds, and herds with a history of reproductive problems such as abortion, giving birth to weak calves, or having swollen testes. Geographic localities with high Brucella seroprevalence occurred in northern, eastern, and southern regions of Kenya all primarily characterized by semi-arid or arid agro-ecological zones dominated by livestock pastoralism interspersed with vast areas with mixed livestock-wildlife systems. The large spatial extent of our survey provides compelling evidence for the widespread geographical distribution of brucellosis risk across Kenya in a manner easily understandable for policymakers. Our findings can provide a basis for risk-stratified pilot studies aiming to investigate the cost-effectiveness and efficacy of singular and combined preventive intervention strategies that seek to inform Kenya's Brucellosis Control Policy.

Utilization of digital tools to enhance COVID-19 and tuberculosis testing and linkage to care: A cross-sectional evaluation study among Bodaboda motorbike riders in the Nairobi Metropolis, Kenya.

Kenya has registered over 300,000 cases of COVID-19 and is a high-burden tuberculosis country. Tuberculosis diagnosis was significantly disrupted by the pandemic. Access to timely diagnosis, which is key to effective management of tuberculosis and COVID-19, can be expanded and made more efficient through integrated screening. Decentralized testing at community level further increases access, especially for underserved populations, and requires robust systems for data and process management. This study delivered integrated COVID-19 and tuberculosis testing to commercial motorbike (Bodaboda) riders, a population at increased risk of both diseases with limited access to services, in four counties: Nairobi, Kiambu, Machakos and Kajiado. Testing sheds were established where riders congregate, with demand creation carried out by the Bodaboda association. Integrated symptom screening for tuberculosis and COVID-19 was conducted through a digital questionnaire which automatically flagged participants who should be tested for either, or both, diseases. Rapid antigen-detecting tests (Ag-RDTs) for COVID-19 were conducted onsite, while sputum samples were collected and transported to laboratories for tuberculosis diagnosis. End-to-end patient data were captured using digital tools. 5663 participants enrolled in the study, 4946 of whom were tested for COVID-19. Ag-RDT positivity rate was 1% but fluctuated widely across counties in line with broader regional trends. Among a subset tested by PCR, positivity was greater in individuals flagged as high risk by the digital tool (8% compared with 4% overall). Of 355 participants tested for tuberculosis, 7 were positive, with the resulting prevalence rate higher than the national average. Over 40% of riders had elevated blood pressure or abnormal sugar levels. The digital tool successfully captured complete end-to-end data for 95% of all participants. This study revealed high rates of undetected disease among Bodaboda riders and demonstrated that integrated diagnosis can be delivered effectively in communities, with the support of digital tools, to maximize access.

Risk factors associated with occurrence of nematodes in free range pigs in Busia District, Kenya.

Nematode infections are a serious constraint to pig production, especially where free range pig keeping is practiced. This study investigated the epidemiology of nematodes in free range pigs in Busia District, Kenya. Three hundred and six pigs from 135 farms were sampled for faeces that were analysed for nematode eggs per gram (EPG) of faeces using the McMaster technique. The nematode eggs were also identified to genus and species based on morphology. A questionnaire on risk factors was also administered to the pig owners. The overall prevalence and mean nematode EPG were 84.2% and 2,355, respectively. The nematode eggs were identified as those belonging to Oesophagostomum spp. (75%), Strongyloides ransomi (37%), Ascaris suum (18%), Metastrongylus spp. (11%), Trichuris suis (7%) and Physocephalus sexalatus (3%). The prevalence of nematodes was positively correlated (p < 0.05) with the amount of rainfall in the division of the pigs' origin (all nematodes except S. ransomi). The prevalence of nematodes was also associated with the age of the pigs. A lower burden of nematodes was associated (p < 0.05) with a history of deworming (A. suum) and the provision of night housing (S. ransomi and Metastrongylus spp.). In conclusion, this study has provided information on nematode infections and the associated risk factors for free range pigs in Busia District, which can be used when implementing integrated control measures.

Six-Months Retention on Treatment and Attrition Risk Factors among People Living with HIV in Kibera Informal Settlement, Nairobi, Kenya.

Early retention of patients on HIV treatment is vital in preventing new infections, reducing transmissions, preventing AIDS related deaths and achieving viral suppression. This study sought to determine the effectiveness of non-cash intervention (reminding HIV positive patients at every clinic visit that they stand to receive free T-shirts of their favorite football team or free Kiondos based on preference if they made it to the sixth month visit without missing a treatment appointment) and psychosocial support on retention during the first six months of HIV treatment. This unblinded randomized control trial was conducted at three health centers within the Kibera informal settlement in Nairobi, Kenya. Participants were randomly assigned to the intervention and control groups at a ratio of 1:1. Eligible participants were patients who newly tested HIV positive and enrolled for treatment at the study sites, were 18 years and older and were willing and able to provide informed consent to participate in the study. The primary outcome of interest was retention on treatment at six months. The overall retention on treatment at six months was 93%. Retention at six months among the intervention and control groups was 94% and 91%, respectively (aRR: 1.03; 95% CI: 0.98-1.09; p-value = 0.24). Attrition from treatment was significantly associated with being divorced, being single/never married, time to clinic, participant weight and being on other first line ART regimens other than TDF/3TC/DTG and TDF/3TC/EFV. Mortality and lost to follow-up rates were 1.6 and 13.5 per 100 person-years, respectively. The combination of non-cash incentives and psychosocial support did not improve retention during the first six months of HIV treatment. To reduce further attrition in the early stages of HIV treatment, innovative strategies are needed to reach divorced and not married/single patients earlier and support them to remain on treatment. Efforts should also be made to further decentralize ART treatment to reduce costs and time associated with travelling to and from hospitals.

Interventions to improve early retention of patients in antiretroviral therapy programmes in sub-Saharan Africa: A systematic review.

BACKGROUND: Several interventions to improve long term retention (12 months and above) on treatment have been rigorously evaluated in Sub-Saharan Africa (SSA). However, research on interventions to improve retention of patients in the early stages of treatment (6 months) during this era of Universal Test and Treat has only recently emerged. The aim of this study is to systematically map evidence of interventions used to improve early retention of patients in antiretroviral therapy (ART) programmes in SSA. METHODS: We searched PubMed, EMBASE and Cochrane electronic databases to identify studies describing interventions aimed at improving early retention in ART treatment. We applied the methodological frameworks by Arksey and O'Malley (2005) and Levac et al. (2010). We also followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Interventions were categorized according to key broad areas in the existing literature. RESULTS: A total of 2,241 articles were identified of which 19 met the inclusion criteria and were eligible for this review, with the majority either being randomized control trials 32% (n = 6) or cohort studies 32% (n = 6). The studies reviewed were conducted in 11 SSA countries. The most common interventions described under key broad areas included: Health system interventions such as Universal Test-and-Treat, integration of ART initiation, HIV Testing and Counselling and Antenatal Care services and reduction of ART drug costs; Patient centered approaches such as fast track ART initiation, Differentiated Drug Delivery models and point of care HIV birth testing; Behavioral interventions and support through lay counselors, mentor mothers, nurse counselors and application of quality improvement interventions and financial incentives. Majority of the studies targeted the HIV positive adults and pregnant women. CONCLUSION: With the introduction of Universal Test-and-Treat and same-day initiation of ART, findings suggest that adoption of policies that expand ART uptake with the goal of reducing HIV transmission at the population level, promoting patient centered approaches such as fast track ART initiation, Differentiated Service Delivery models and providing adequate support through Mentor Mothers, lay and nurse counselors may improve early retention in HIV care in SSA. However, these interventions have only been tested in few countries in the region which points to how hard evidence based HIV programming is. Further research investigating the impact of individual and a combination of interventions to improve early retention in HIV care, including for various groups at high risk of attrition, is warranted across SSA countries to fast track the achievement of 95-95-95 Joint United Nations Programme on HIV/AIDS (UNAIDS) targets by 2030.