An update on the distribution, bionomics, and insecticide susceptibility of Anopheles stephensi in Ethiopia, 2018-2020.

BACKGROUND: Anopheles stephensi, an invasive malaria vector, was first detected in Africa nearly 10 years ago. After the initial finding in Djibouti, it has subsequently been found in Ethiopia, Sudan and Somalia. To better inform policies and vector control decisions, it is important to understand the distribution, bionomics, insecticide susceptibility, and transmission potential of An. stephensi. These aspects were studied as part of routine entomological monitoring in Ethiopia between 2018 and 2020. METHODS: Adult mosquitoes were collected using human landing collections, pyrethrum spray catches, CDC light traps, animal-baited tent traps, resting boxes, and manual aspiration from animal shelters. Larvae were collected using hand-held dippers. The source of blood in blood-fed mosquitoes and the presence of sporozoites was assessed through enzyme-linked immunosorbent assays (ELISA). Insecticide susceptibility was assessed for pyrethroids, organophosphates and carbamates. RESULTS: Adult An. stephensi were collected with aspiration, black resting boxes, and animal-baited traps collecting the highest numbers of mosquitoes. Although sampling efforts were geographically widespread, An. stephensi larvae were collected in urban and rural sites in eastern Ethiopia, but An. stephensi larvae were not found in western Ethiopian sites. Blood-meal analysis revealed a high proportion of blood meals that were taken from goats, and only a small proportion from humans. Plasmodium vivax was detected in wild-collected An. stephensi. High levels of insecticide resistance were detected to pyrethroids, carbamates and organophosphates. Pre-exposure to piperonyl butoxide increased susceptibility to pyrethroids. Larvae were found to be susceptible to temephos. CONCLUSIONS: Understanding the bionomics, insecticide susceptibility and distribution of An. stephensi will improve the quality of a national response in Ethiopia and provide additional information on populations of this invasive species in Africa. Further work is needed to understand the role that An. stephensi will have in Plasmodium transmission and malaria case incidence. While additional data are being collected, national programmes can use the available data to formulate and operationalize national strategies against the threat of An. stephensi.

Prevalence of intestinal parasites and associated risk factors among inmates of Mekelle prison, Tigrai Region, Northern Ethiopia, 2017.

BACKGROUND: In Ethiopia, like other developing countries, intestinal parasitic infections are the major public health problems affecting millions annually. Overcrowding and poor living conditions are the major risk factors. Prison inmates are among the most vulnerable groups to intestinal parasitic infections. However, there is scarcity of epidemiological data regarding intestinal parasites among prison inmates in Ethiopia, notably in Tigrai. Thus, we aimed to determine the prevalence of intestinal parasites and identify the associated factors among inmates of Mekelle prison, Tigrai, Northern Ethiopia. METHODS: A cross sectional study involving 291 inmates was conducted from February to June 2017 among inmates of Mekelle prison. After systematically selecting subjects, stool specimens were examined using direct wet mount and formol-ether concentration techniques. We used SPSS version 21 for data analysis. We considered p-value less than 0.05 significant at 95% confidence level. RESULTS: Of the 291 inmates enrolled in the study, 124 (42.6%) harbored one or more intestinal parasites. The protozoan Entamoeba histolytica/dispar/moshkovskii was the predominant parasite accounted for 68 (23.3%) of the infections followed by Giardia lamblia (10.3%) and Entamoeba coli (8.2%). Fourteen (4.8%) participants were co-infected with different parasite species. The co-infections of Entamoeba histolytica/dispar/moshkovskii and Giardia lamblia were detected among 3.1% of the participants. In bivariate analysis, hand fingernail status (COR 1.86, 95% CI, 1.08-3.20) and duration of stay in prison (COR 2.23, 95% CI 1.31-3.79) were statistically associated with intestinal parasite infections. In multivariable regression, inmates who stayed in the prison for one year or less were more likely to harbor intestinal parasitic infections (p = 0.013) than those who stayed longer. No other single predictor variable was found to be significantly associated with intestinal parasitic infections. CONCLUSIONS: The result of this study showed that intestinal parasites are significant health problems among inmates of Mekelle prison.

Insecticide resistance in Anopheles arabiensis from Ethiopia (2012-2016): a nationwide study for insecticide resistance monitoring.

BACKGROUND: Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) remain the cornerstones of malaria vector control. However, the development of insecticide resistance and its implications for operational failure of preventative strategies are of concern. The aim of this study was to characterize insecticide resistance among Anopheles arabiensis populations in Ethiopia and describe temporal and spatial patterns of resistance between 2012 and 2016. METHODS: Between 2012 and 2016, resistance status of An. arabiensis was assessed annually during the long rainy seasons in study sites from seven of the nine regions in Ethiopia. Insecticide resistance levels were measured with WHO susceptibility tests and CDC bottle bioassays using insecticides from four chemical classes (organochlorines, pyrethroids, organophosphates and carbamates), with minor variations in insecticides tested and assays conducted between years. In selected sites, CDC synergist assays were performed by pre-exposing mosquitoes to piperonyl butoxide (PBO). In 2015 and 2016, mosquitoes from DDT and deltamethrin bioassays were randomly selected, identified to species-level and screened for knockdown resistance (kdr) by PCR. RESULTS: Intense resistance to DDT and pyrethroids was pervasive across Ethiopia, consistent with historic use of DDT for IRS and concomitant increases in insecticide-treated net coverage over the last 15 years. Longitudinal resistance trends to malathion, bendiocarb, propoxur and pirimiphos-methyl corresponded to shifts in the national insecticide policy. By 2016, resistance to the latter two insecticides had emerged, with the potential to jeopardize future long-term effectiveness of vector control activities in these areas. Between 2015 and 2016, the West African (L1014F) kdr allele was detected in 74.1% (n = 686/926) of specimens, with frequencies ranging from 31 to 100% and 33 to 100% in survivors from DDT and deltamethrin bioassays, respectively. Restoration of mosquito susceptibility, following pre-exposure to PBO, along with a lack of association between kdr allele frequency and An. arabiensis mortality rate, both indicate metabolic and target-site mutation mechanisms are contributing to insecticide resistance. CONCLUSIONS: Data generated by this study will strengthen the National Malaria Control Programme's insecticide resistance management strategy to safeguard continued efficacy of IRS and other malaria control methods in Ethiopia.

Factors influencing the uptake of voluntary HIV counseling and testing in rural Ethiopia: a cross sectional study.

BACKGROUND: Voluntary counseling and testing (VCT) has been one of the key policy responses to the HIV/AIDS epidemic in Ethiopia. However, the utilization of VCT has been low in the rural areas of the country. Understanding factors influencing the utilization of VCT provides information for the design of context based appropriate strategies that aim to improve utilization. This study examined the effects of socio-demographic and behavioral factors, and health service characteristics on the uptake of VCT among rural adults in Ethiopian. METHODS/DESIGN: This study was designed as a cross sectional study. Data from 11,919 adults (6278 women aged 15-49 years and 5641 men aged 15-59 years) residing in rural areas of Ethiopia who participated in a national health extension program evaluation were used for this study. The participants were selected from ten administrative regions using stratified multi-stage cluster sampling. Multivariate logistic regression analysis was performed accounting for factors associated with the use of VCT service. RESULTS: Overall, men (28 %) were relatively more likely to get tested for HIV than women (23.7 %) through VCT. Rural men and women who were young and better educated, who perceived having small risk of HIV infection, who had comprehensive knowledge, no stigmatization attitude and discussed about HIV/AIDS with their partner, and model-family were more likely to undergone VCT. Regional state was also strongly associated with VCT utilization in both men and women. Rural women who belonged to households with higher socio-economic status, non-farming occupation, female-headed household and located near health facility, and who visited health extension workers and participated in community conversation were more likely to use VCT. Among men, agrarian lifestyle was associated with VCT use. CONCLUSIONS: Utilization of VCT in the rural communities is low, and socio-economic, behavioral and health service factors influence its utilization. For increasing the utilization of VCT service in rural areas, there is a need to target the less educated, women, poor and farming families with a focus on improving knowledge and reducing HIV/AIDS related stigma. Strategy should include promoting partner and community conversations, accelerating model-family training, and using alternative modes of testing.

Continuous resin tapping for frankincense harvest increases susceptibility of Boswellia papyrifera (Del.) Hochst trees to longhorn beetle damage.

Frankincense is an important tree resin that provides a livelihood in the semi-arid lower highlands of East Africa. In the absence of sustainable management strategies, Boswellia papyrifera trees were being overexploited, leading to a depletion of genetic diversity, affected by pests and diseases, failure in natural regeneration, and hence a subsequent decline in socio-ecological benefits obtained from the species. We studied the impact of (i) continuous resin tapping without resting years and (ii) tapping or wonding intensity for frankincence production on the prevalence of longhorn beetle (Idactus spinipennis Gahan, Cerambycidae (sub family Lamiinae) damage in northern Ethiopia. We found that continuous resin tapping for frankincense harvest without adequate resting period made trees more vulnerable to longhorn beetle damage (P < 0.05). Trees rested for 10 and more years from resin tapping had less beetle damage occurrence than those tapped continuously (P < 0.05). Stem tapping intensity of more than 12 wounds per tree in one frankincense harvesting season caused high longhorn beetle damage incidence in Central Tigray (up to 90%) and Western Tigray (up to 80%). We recommend that B. papyrifera trees should have a resting period of at least 3 years and more after one year of continuous tapping. Depending on the size of a tree, wounding for frankincense harvest should be restricted to less than 12 wounds per tree. These measures would help the species develop resistance to longhorn beetle attack and maintain a healthy population for sustainable provision of ecosystem services including frankincense production in the dryalnds of northern Ethiopia.

Prevalence and environmental determinants of cutaneous leishmaniasis in rural communities in Tigray, northern Ethiopia.

BACKGROUND: In Ethiopia guidelines for diagnoses and treatment of leishmaniases are available, but only a few hundred people are diagnosed and receive treatment. A field study has been carried out to determine the status and environmental determinants of cutaneous leishmaniasis (CL) and assess the degree of awareness of the rural communities in affected areas in Tigray, northern Ethiopia. METHODOLOGY / PRINCIPAL FINDINGS: Following a reconnaissance survey that identified endemic foci, a cross sectional door-to-door survey was conducted in 2009 in five rural communities around the towns of Adigrat and Hagereselam in Tigray. In total 9,622 residents of 1,721 households were clinically screened and household heads interviewed regarding the determinants of infection. The χ2 test and logistic regression were used to determine differences in prevalence between localities, age and sex, and to identify environmental determinants of infection. The overall prevalence of localized CL was 2.3% (highest 4.7%), with marked inter-village differences. Another 20.9% had scars from previous infections. While risk was sex-independent, prevalence was significantly higher in the 0-9 (4.5%) and 10-19 (2.5%) age groups and predominantly involved the face (82.1%) and upper limbs (13.1%). Nearly 11% of the households had one or more cases of CL and this was associated with proximity to hyrax habitats. All interviewees were knowledgeable about the lesions but ignorant of the disease's mode of transmission and its association with hyraxes. CONCLUSIONS: The study established that CL is an important public health problem in the study communities, and has been so for a while, as demonstrated by the widespread presence of scars. CL in Tigray appeared to be predominantly of zoonotic nature, mainly transmitted in peri-domestic habitats in proximity to hyrax habitats. Integrated interventions, including awareness creation, are highly recommended.

Assessment of community knowledge, practice, and determinants of malaria case households in the rural area of Raya Azebo district, Northern Ethiopia, 2017.

BACKGROUND: In Ethiopia malaria is one of the leading causes of outpatient visits and admission. Still, it remains a major cause of morbidity and mortality in the study area. Therefore, this study was aimed to assess the knowledge, practice, and determinant of malaria case households in rural areas of Raya Azebo district, Northern Ethiopia. METHOD: A community-based cross-sectional survey was conducted in the selected villages of Raya Azebo district from January to June 2017. A multi-stage random sampling method was employed to select a total of 422 study households. Data was collected using a semi-structured questionnaire. The household head was interviewed face to face. Logistic regression analysis was used to determine the determinant of malaria cases households. RESULT: A total of 412 (97.6) of the respondents had ever heard about malaria. About 63% of households recognized the causes of malaria to be a mosquito bite. Around 173 (41%) of the study households had been treated for malaria within a year of data collection. This study also revealed that the presence of mosquito breeding sites near to home, bed bug infestation, outdoor sleep due to bed bugs and household with poor bed net practicing were significantly associated with malaria case households. CONCLUSION: Although the overall knowledge on malaria transmission, symptoms, and the preventive measure was relatively good, the rate of household insecticide-treated net coverage and utilization were reported low in the area. Therefore, the distribution of adequate bed net with community-based education is a key intervention to promote household insecticide-treated net utilization. In addition, an effective bed bug management strategy is necessary to overcome the outdoor sleeping habit of the community in the area.

Microbiological Safety of Street Vended Foods in Jigjiga City, Eastern Ethiopia.

BACKGROUND: Food safety problems are particularly becoming an increasingly serious threat to public health in developing countries. This study was conducted to assess microbiological safety of street vended foods from May to November, 2014 in Jigjiga City. METHODS: A cross-sectional design was used to answer questions concerning the current status of food hygiene and sanitation practire of street food vending sites. Interview and observational assessments were used to collect socio-demographic data about street food venders. One hundred thirty-two samples of street foods were aseptically collected from four 'kebeles' of Jigjiga City. Both descriptive and analytical statistical methods were applied. RESULTS: The majority of the street food vendors were women, 120(90.9%), with the average age group of 23-49 years, (42.85%), and 99(66.7%) them were illiterate. The study revealed that 95(72%) of the food samples had pathogenic bacterial contaminations. Three different bacterial species were isolated: E. coli 68(51.5%), S. aureus 85(64.4%) and 26(19.7%) Salmonella species. The highest incidence of S. aureus 23/33(69%) was seen in 'Sambusa'; the highest incidence of E. coli 24/33(73.5%) was observed in 'Pasta', while the highest Salmonella incidence was observed in 'Ades'. CONCLUSION: This study revealed that there is a reasonable gap on food safety knowledge among street food venders. The microbial profile was also higher compared to standards set by the World Health Organization. Due attention should be given by the government to improve knowledge about food safety and the quality standard of street foods sold in the City.

Epidemiological study of cutaneous leishmaniasis in Saesie Tsaeda-emba district, eastern Tigray, northern Ethiopia.

BACKGROUND: Cutaneous leishmaniasis (CL) is one of the endemic and neglected diseases known to exist in Ethiopian highlands. However, little is known about its epidemiological characteristics. Hence, this study was initiated and conducted from November 2011 to April 2012 to assess the epidemiological situation of CL in Saesie Tsaeda-emba District. METHODS: A cross sectional design was employed in six randomly selected Peasant associations and a house to house survey was carried out in the District. Detailed clinical assessment, and smear and culture for Leishmania parasite detection were done to confirm clinical suspension. Polymerase Chain Reaction and Restriction Fragment Length Polymorphism (PCR-RFLP) analysis of the ribosomal DNA Internal Transcribed Spacer (ITS-1) sequences was used to type isolates. Sandfly collection was also conducted in possible micro-habitats of the target areas. RESULTS: The overall prevalence of CL in the District was 14.0% (6.7% for active lesion and 7.3% for scar) with the highest prevalence amongst the age group of 10-19 years. Field isolates typed were L. aethiopica. Environmental and host risk factors significantly associated with CL distribution were age, study Peasant associations, presence of cave/gorge, walls with cracks and/or holes, presence of hyrax, animal burrow, animal dung and farm land near to residents' houses. Five phlebotomine sandflies, Phlebotomus longipes, Sergentomyia bedfordi, S.africana, S.schwetzi and S.antenata were captured. CONCLUSION: All the precipitating factors in the area are indicative of the public health importance of CL although there has been little attention given. The present study is a starter for wider investigation into the mode of its transmission, incrimination of sandfly vectors and possible animal reservoirs. Detailed information will be the basis to launch effective control of CL in the area.

Emerging chronic non-communicable diseases in rural communities of Northern Ethiopia: evidence using population-based verbal autopsy method in Kilite Awlaelo surveillance site.

INTRODUCTION: In countries where most deaths are outside health institutions and medical certification of death is absent, verbal autopsy (VA) method is used to estimate population level causes of death. METHODS: VA data were collected by trained lay interviewers for 409 deaths in the surveillance site. Two physicians independently assigned cause of death using the International Classification of Diseases manual. RESULTS: In general, infectious and parasitic diseases accounted for 35.9% of death, external causes 15.9%, diseases of the circulatory system 13.4% and perinatal causes 12.5% of total deaths. Mortalities attributed to maternal causes and malnutrition were low, 0.2 and 1.5%, respectively. Causes of death varied by age category. About 22.1, 12.6 and 8.4% of all deaths of under 5-year-old children were due to bacterial sepsis of the newborn, acute lower respiratory infections such as neonatal pneumonia and prematurity including respiratory distress, respectively. For 5-15-year-old children, accidental drowning and submersion, accounting for 34.4% of all deaths in this age category, and accidental fall, accounting for 18.8%, were leading causes of death. Among 15-49-year-old adults, HIV/AIDS (16.3%) and tuberculosis (12.8%) were commonest causes of death, whereas tuberculosis and cerebrovascular diseases were major killers of those aged 50 years and above. CONCLUSION: In the rural district, mortality due to chronic non-communicable diseases was very high. The observed magnitude of death from chronic non-communicable disease is unlikely to be unique to this district. Thus, formulation of chronic disease prevention and control strategies is recommended.

Characterization of mosquito breeding sites in and in the vicinity of tigray microdams.

BACKGROUND: Malaria vector control in Ethiopia has a history of more than 50 years, but malaria remains a major cause of morbidity and mortality in Ethiopia. Thus, targeting the control program on the larval stage is of paramount importance. This study aimed to characterize the aquatic habitats of vector mosquito larvae associated with micro-dams. METHODS: Cross-sectional larval survey was conducted on six micro-dams in Tigray, Northern Ethiopia in 2005/06. The study area on each dam was divided into eight zones. Immature stages of mosquitoes were collected using standard dippers. The physico-chemical characteristics of the aquatic habitats were measured onsite. RESULTS: A total of 301 aquatic habitats were surveyed for mosquito larvae; in 32.56% (n=301) only Anopheles, in 27.91% only Culex, both genera were found mixed in 21.59% and no mosquito larvae were found in 17.94%. The findings depicted that dissolved oxygen (r = 0.34, p =0.04), pH (r = 0.35, p =0.03), conductivity (r = 0.36, p =0.03), vegetation (F = 3.54, p =0.002), microhabitat (F = 2.65, p =0.04), fauna and bottom surface of the water body were positively associated and important in explaining the presence and abundance of Culex. On the other hand, dissolved oxygen (r = 0.39, p =0.02), pH (r = 0.42, p =0.008), vegetation (F = 5.6, p =0.000), water transparency (F = 2.72, p =0.00), rainfall (F = 2.22, p = 0.027) and fauna were positively associated and important in explaining the presence and abundance of Anopheles. CONCLUSION: The findings of this study suggest that both biotic (vegetation and fauna) and abiotic (chemical and physical) factors play a significant role in larvae's habitat preference in both Culex and Anopheles.

Can source reduction of mosquito larval habitat reduce malaria transmission in Tigray, Ethiopia?

The development of irrigation schemes by dam construction has led to an increased risk of malaria in Tigray, Ethiopia. We carried out a pilot study near a microdam to assess whether environmental management could reduce malaria transmission by Anopheles arabiensis, the main vector in Ethiopia. The study took place in Deba village, close to a dam; Maisheru village, situated 3-4 km away from the dam, acted as a control. Baseline entomological and clinical data were collected in both villages during the first 12 months. Source reduction, involving filling, draining and shading of potential mosquito-breeding habitats was carried out by the community of Deba in the second year and routine surveillance continued in both villages during the second year. Anopheles arabiensis was highly anthropophilic (Human Blood Index=0.73), biting early in the night before people went to bed. The major breeding habitats associated with the dam were areas of seepage at the dam base (28%), leaking irrigation canals (16%), pools that formed along the bed of streams from the dam (13%), and man-made pools (12%). In the pre-intervention year, 5.9-7.2 times more adult vectors were found in the dam village compared with the control village. There was a 3.1% higher prevalence of an enlarged spleen in children under 10 years in the dam village than in the control village during the pre-intervention period, but no statistically significant difference was found in the incidence of falciparum malaria between the two villages during the same period. Source reduction was associated with a 49% (95% CI=46.6-50.0) relative reduction in An. arabiensis adults in the dam village compared with the pre-intervention period. There were very few cases of malaria during the intervention period in both villages making it impossible to judge whether malaria incidence had been reduced. These preliminary findings suggest that in areas of low intensity transmission community-led larval control may be a cheap and effective method of controlling malaria. Further, large-scale studies are needed to confirm these findings.