Modelling of Hepatitis B Virus vertical transmission dynamics in Ethiopia: a compartmental modelling approach.

BACKGROUND: Hepatitis B (HB) is a virus which causes a potentially fatal liver infection. It is a DNA virus belonging to the Hepadnaviridae virus family. Africa, after Asia, has the second highest number of chronic HBV carriers and is considered a high-endemic region. Ethiopia is classified as a country with a high prevalence of viral hepatitis and with nations that lack a systematic strategy for viral hepatitis surveillance. METHODS: S-I-C-R deterministic model was developed and the numerical simulations were done in "R" statistical and programming software. Fixed population assumption was considered so as to develop a simple model which could predict the HBV vertical transmission for the next 5 decades. RESULTS: The model revealed that significant number of populations will be infected and become carrier till the end the next 49 years even though it has decreasing trend. It was predicted that 271,719 people will die of HBV complications if no intervention will be made on its vertical transmission. The sensitivity analysis result showed that the force of infection has the most important parameter in the vertical transmission dynamics of hepatitis B. Provision of hepatitis B immunoglobulin (HBVIG) and vaccines at the time of delivery could decrease the force of infection by more than half and 51,892 lives will be saved if the intervention is offered for 50% of deliveries in Ethiopia. CONCLUSION: Despite the fact that the incidence of HBV vertical transmission is substantial, it is expected to decline during the next five decades. However, the situation necessitates immediate attention, since it results in thousands of deaths if no action is taken. Offering HBVIG and vaccinations to the 50% of infants can save many lives and reduces the force of infection by more than a half.

Revisiting the Natural History of Pulmonary Tuberculosis: A Bayesian Estimation of Natural Recovery and Mortality Rates.

BACKGROUND: Tuberculosis (TB) natural history remains poorly characterized, and new investigations are impossible as it would be unethical to follow up TB patients without treatment. METHODS: We considered the reports identified in a previous systematic review of studies from the prechemotherapy era, and extracted detailed data on mortality over time. We used a Bayesian framework to estimate the rates of TB-induced mortality and self-cure. A hierarchical model was employed to allow estimates to vary by cohort. Inference was performed separately for smear-positive TB (SP-TB) and smear-negative TB (SN-TB). RESULTS: We included 41 cohorts of SP-TB patients and 19 cohorts of pulmonary SN-TB patients in the analysis. The median estimates of the TB-specific mortality rates were 0.389 year-1 (95% credible interval [CrI], .335-.449) and 0.025 year-1 (95% CrI, .017-.035) for SP-TB and SN-TB patients, respectively. The estimates for self-recovery rates were 0.231 year-1 (95% CrI, .177-.288) and 0.130 year-1 (95% CrI, .073-.209) for SP-TB and SN-TB patients, respectively. These rates correspond to average durations of untreated TB of 1.57 years (95% CrI, 1.37-1.81) and 5.35 years (95% CrI, 3.42-8.23) for SP-TB and SN-TB, respectively, when assuming a non-TB-related mortality rate of 0.014 year-1 (ie, a 70-year life expectancy). CONCLUSIONS: TB-specific mortality rates are around 15 times higher for SP-TB than for SN-TB patients. This difference was underestimated dramatically in previous TB modeling studies, raising concerns about the accuracy of the associated predictions. Despite being less infectious, SN-TB may be responsible for equivalent numbers of secondary infections as SP-TB due to its much longer duration.

Heterogeneous infectiousness in mathematical models of tuberculosis: A systematic review.

TB mathematical models employ various assumptions and approaches in dealing with the heterogeneous infectiousness of persons with active TB. We reviewed existing approaches and considered the relationship between them and existing epidemiological evidence. We searched the following electronic bibliographic databases from inception to 9 October 2018: MEDLINE, EMBASE, Biosis, Global Health and Scopus. Two investigators extracted data using a standardised data extraction tool. We included in the review any transmission dynamic model of M. tuberculosis transmission explicitly simulating heterogeneous infectiousness of person with active TB. We extracted information including: study objective, model structure, number of active TB compartments, factors used to stratify the active TB compartment, relative infectiousness of each active TB compartment and any intervention evaluated in the model. Our search returned 1899 unique references, of which the full text of 454 records were assessed for eligibility, and 99 studies met the inclusion criteria. Of these, 89 used compartmental models implemented with ordinary differential equations, while the most common approach to stratification of the active TB compartment was to incorporate two levels of infectiousness. However, various clinical characteristics were used to stratify the active TB compartments, and models differed as to whether they permitted transition between these states. Thirty-four models stratified the infectious compartment according to sputum smear status or pulmonary involvement, while 18 models stratified based on health care-related factors. Variation in infectiousness associated with drug-resistant M. tuberculosis was the rationale for stratifying active TB in 33 models, with these models consistently assuming that drug-resistant active TB cases were less infectious. Given the evidence of extensive heterogeneity in infectiousness of individuals with active TB, an argument exists for incorporating heterogeneous infectiousness, although this should be considered in light of the objectives of the study and the research question. PROSPERO Registration: CRD42019111936.

The role of super-spreading events in Mycobacterium tuberculosis transmission: evidence from contact tracing.

BACKGROUND: In current epidemiology of tuberculosis (TB), heterogeneity in infectiousness among TB patients is a challenge, which is not well studied. We aimed to quantify this heterogeneity and the presence of "super-spreading" events that can assist in designing optimal public health interventions. METHODS: TB epidemiologic investigation data notified between 1 January 2005 and 31 December 2015 from Victoria, Australia were used to quantify TB patients' heterogeneity in infectiousness and super-spreading events. We fitted a negative binomial offspring distribution (NBD) for the number of secondary infections and secondary active TB disease each TB patient produced. The dispersion parameter, k, of the NBD measures the level of heterogeneity, where low values of k (e.g. k < 1) indicate over-dispersion. Super-spreading was defined as patients causing as many or more secondary infections as the 99th centile of an equivalent homogeneous distribution. Contact infection was determined based on a tuberculin skin test (TST) result of ≥10 mm. A NBD model was fitted to identify index characteristics that were associated with the number of contacts infected and risk ratios (RRs) were used to quantify the strength of this association. RESULTS: There were 4190 (2312 pulmonary and 1878 extrapulmonary) index TB patients and 18,030 contacts. A total of 15,522 contacts were tested with TST, of whom 3213 had a result of ≥10 mm. The dispersion parameter, k for secondary infections was estimated at 0.16 (95%CI 0.14-0.17) and there were 414 (9.9%) super-spreading events. From the 3213 secondary infections, 2415 (75.2%) were due to super-spreading events. There were 226 contacts who developed active TB disease and a higher level of heterogeneity was found for this outcome than for secondary infection, with k estimated at 0.036 (95%CI 0.025-0.046). In regression analyses, we found that infectiousness was greater among index patients found by clinical presentation and those with bacteriological confirmation. CONCLUSION: TB transmission is highly over dispersed and super-spreading events are responsible for a substantial majority of secondary infections. Heterogeneity of transmission and super-spreading are critical issues to consider in the design of interventions and models of TB transmission dynamics.

The Importance of Heterogeneity to the Epidemiology of Tuberculosis.

Although less well-recognized than for other infectious diseases, heterogeneity is a defining feature of tuberculosis (TB) epidemiology. To advance toward TB elimination, this heterogeneity must be better understood and addressed. Drivers of heterogeneity in TB epidemiology act at the level of the infectious host, organism, susceptible host, environment, and distal determinants. These effects may be amplified by social mixing patterns, while the variable latent period between infection and disease may mask heterogeneity in transmission. Reliance on notified cases may lead to misidentification of the most affected groups, as case detection is often poorest where prevalence is highest. Assuming that average rates apply across diverse groups and ignoring the effects of cohort selection may result in misunderstanding of the epidemic and the anticipated effects of control measures. Given this substantial heterogeneity, interventions targeting high-risk groups based on location, social determinants, or comorbidities could improve efficiency, but raise ethical and equity considerations.

Antigen Detection in Urine for Noninvasive Diagnosis and Treatment Monitoring of Visceral Leishmaniasis in Human Immunodeficiency Virus Coinfected Patients: An Exploratory Analysis from Ethiopia.

Diagnosis of visceral leishmaniasis (VL) and assessment of treatment response in human immunodeficiency virus (HIV)-coinfected patients still relies on invasive tissue aspiration. This hampers scale-up and decentralization of care in resource-limited settings. Noninvasive diagnostics are urgently needed. KATEX is a frequently used latex agglutination test for Leishmania antigen in urine that has never been evaluated in HIV-coinfected individuals from Leishmania donovani-endemic areas. This was an exploratory sub-study embedded within the screening phase of a trial in highly endemic northwestern Ethiopia. All patients were HIV-positive and aspirate-confirmed VL cases. We assessed diagnostic accuracy of KATEX for VL diagnosis and as test of cure at end of treatment, using tissue aspirate parasite load as reference methods. We also described the evolution of weekly antigen levels during treatment. Most of the 87 included patients were male (84, 97%), young (median age 31 years), and had poor immune status (median cluster of differentiation type 4 count 56 cells/µL). KATEX had moderate sensitivity (84%) for VL diagnosis. KATEX had moderate sensitivity (82%) and a moderate negative predictive value (87%) but only low specificity (49%) and a low positive predictive value (40%) for the assessment of treatment outcomes. Weekly antigen levels showed characteristic patterns during treatment of patients with different initial parasite loads and treatment outcomes. Antigen detection in urine using KATEX can contribute to improved VL diagnosis in HIV-coinfected patients but has limited use for monitoring of treatment response. Better noninvasive diagnostics are needed to reduce reliance on invasive methods and thus to expand and improve clinical care for VL in resource-limited settings.

Prevalence of stunting and its associated factors among children 6-59 months of age in Libo-Kemekem district, Northwest Ethiopia; A community based cross sectional study.

BACKGROUND: Children in developing countries are highly vulnerable to impaired physical growth because of poor dietary intake, lack of appropriate care, and repeated infections. This study aimed at assessing the prevalence of stunting and associated factors among children 6-59 months of age in Libo-kemekem district, northwest Ethiopia. METHODS: A community based cross sectional study was conducted in Libo-Kemekem from October 15 to December 15, 2015. The multistage sampling technique was employed to select 1,320 children aged 6-59months. Data were collected by trained community health extension workers under regular supervision. Data were entered into EPI-Info version 3.5.1, and height for age was converted to Z-score with ENA-SMART software. Data were then exported to SPSS version 20 for descriptive and binary logistic regression analysees. The significance of associations was determined at p<0.05. RESULTS: Out of 1287 children included in the analysis, 49.4% (95% CI: 46.7%-52.3%) were found to be stunted. In the multivariate analysis, increased child age [AOR = 6.31, 95%CI: (3.65, 10.91)], family size of six and above [AOR = 1.77, 95%CI: (1.35, 2.32)] were positively associated with stunting, while, fathers with secondary school education [AOR = 0.50, 95%CI: (0.30, 0.81)], farmers as household heads [AOR = 0.56, 95%CI: (0.38, 0.84)] and self-employed parents as household head [AOR = 0.45, 95% CI: (0.28, 0.72)] were found to be preventive factors. CONCLUSION: The prevalence of stunting was high in the study area. We found that stunting was significantly correlated with child age, occupational status of household head, family size, and fathers' education. Therefore, intervention focusing on supporting housewives, family planning, and education on child feeding and nutrition should be implemented.

Sick at work: prevalence and determinants among healthcare workers, western Ethiopia: an institution based cross-sectional study.

BACKGROUND: Going to work despite feeling sick also known as sickness presenteeism is one of the emerging global occupational health challenges. Sickness presenteeism negatively affects both health of work forces and productivity of organizations in general. However, there is insufficient research exploring this situation in majority of the Sub-Saharan African countries, including Ethiopia. Thus this study intended to investigate the prevalence and determinant factors of sickness presenteeism among health care workers, Western Ethiopia. METHODS: This study used an institution based cross-sectional quantitative study design. The study period was from February to March, 2017. We employed simple random sampling method to select 360 study samples. Data collection was performed by pre-tested structured and self- administered questionnaire. We used SPSS version 20 to carry out binary logistic regression analysis. Odds ratio with 95% confidence intervals was calculated and significance of associations was determined at p-value < 0.05. RESULTS: A total of 344 respondents fully completed the survey questionnaire. Mean age with standard deviation was 30.28 ± 6.181. Prevalence of sickness Presenteeism was 52.6% [95%CI: (47.4, 57.8)] in the past 12 months. Educational status [AOR:2.1, 95%CI: (1.17,3.90)], financial problem [AOR:1.9,95%CI:(1.07,3.46)], sickness absenteeism [AOR:2.7,95% CI:(1.50,5.02)], lack of staff replacement [AOR:2.7,95%CI:(1.50,5.02)], absence of occupational health services [AOR:3.0,95%CI:(1.34,6.70)], and pressure from supervisor [AOR:1.8,95% CI:(1.01,3.31)] were significant predictors of the dependent variable. CONCLUSION: Relatively higher proportions of workers indicated sickness presenteeism as compared to other studies. Risk factors like educational status, personal financial problem, sickness absenteeism, lack of staff replacement, absence of occupational health services, and pressure from supervisors considerably increased the likely occurrence of employees' sick attendance. It is advisable for health care managers to hire adequate health care staffs, to implement basic occupational health services and to design strategies which reduce pressure from supervisors.

Exclusive breastfeeding and mothers' employment status in Gondar town, Northwest Ethiopia: a comparative cross-sectional study.

BACKGROUND: Exclusive breastfeeding is defined as feeding an infant breast milk only, for the first six months. In Ethiopia, more than half of infants do not receive exclusive breastfeeding. Workplace barriers contribute to these low rates of exclusive breastfeeding practices. Understanding the sociodemographic, health related, behavioral and economic factors is crucial to promote the practice of exclusive breastfeeding in Ethiopia. Therefore, the aim of this study was to assess the extent of exclusive breastfeeding practice and associated factors among employed and unemployed mothers with children of age 7-12 months in Gondar town, northwest Ethiopia, 2015. METHODS: A community based comparative cross-sectional study was conducted in October 2015. Simple random sampling technique was used to select 649 eligible mothers with children age 7-12 months during the study period. A structured and pretested interviewer administered questionnaire was used to collect the data. Three logistic regression models: whole sample, employed and not employed, were fitted. RESULTS: A total of 649 (333 unemployed and 316 employed) mothers were interviewed. The mean duration of mothers to exclusively breastfeed was 4.77 months (± 1.36 Standard Deviation [SD]). Exclusive breastfeeding was higher among unemployed 48.0% with 95% Confidence Interval (CI) (42.0%, 54.0%) than employed (20.9%) with 95% CI (16.0%, 25.0%). Parity of three children and above (Adjusted Odds Ratio [AOR] = 3.48), and having social support (AOR = 3.45) were positively associated with exclusive breastfeeding while poor knowledge (AOR = 0.30), wealth index of the medium level (AOR = 0.38) were negatively associated among employed mothers. In the case of unemployed mothers, vaginal delivery (AOR = 2.60) and having social support (AOR = 3.03) were positively associated with exclusive breastfeeding while, poor knowledge (AOR = 0.28), and not having antenatal care (AOR = 0.56) were negatively associated. CONCLUSIONS: The overall exclusive breastfeeding practice of mothers was low. However, unemployed mothers breastfeed more than employed mothers. Providing a special support for employed mothers and revising either the legislation of the two month postpartum maternity leave or applying different alternatives is recommended.

Peripheral Sensory Neuropathy and associated factors among adult diabetes mellitus patients in Bahr Dar, Ethiopia.

BACKGROUND: Diabetic sensory neuropathy is a common form of microvascular complication among diabetic patients. The swiftly growing population of people living with diabetes in Ethiopia and lack of elaborated scientific data on peripheral sensory neuropathy among diabetic population in Ethiopia prompted this work. This study was set out to assess the enormity and associated factors of peripheral sensory neuropathy among diabetes patients attending chronic illness clinic of Felege Hiwot Regional Referral Hospital, Bahr Dar, Northwest Ethiopia. METHODS: An institution based cross-sectional study was conducted at Felege Hiwot Referral Hospital chronic illness clinic using Michigan neuropathy screening instrument tool for diabetic peripheral sensory neuropathy on 408 diabetic patients during 2016. Data were collected using interview, patient record review, anthropometric measurements and physical examination. Both bivariate and multivariate binary logistic regression was employed to identify factors associated with peripheral sensory neuropathy. Odds ratios with their 95% CI and P value less than 0.05 used to determine statistically significant associations. RESULTS: A total of 368 patients were included with the mean age of 49 ± 14.3 years. The overall prevalence of Peripheral Sensory Neuropathy was found to be 52.2%. The major associated factors identified by multivariate analysis were age >50 years: AOR: 3.0 CI [1.11, 7.89]; overweight and obese: AOR: 7.3 CI [3.57, 14.99]; duration of DM: AOR: 3.4 CI [1.75, 6.60]; not involved in physical exercise: AOR: 4.8 CI [1.90, 7.89]; male gender: AOR: 2.4 CI [1.18, 5.05]. CONCLUSION: Almost half of the diabetic patients who attended Felege Hiwot regional referral hospital during study period were found to present with peripheral sensory neuropathy. Socio-demographic and bio characteristics like patients age, Body Mass Index, level of physical activity and marital status were significantly associated with diabetic peripheral sensory neuropathy.

Maternal health care service seeking behaviors and associated factors among women in rural Haramaya District, Eastern Ethiopia: a triangulated community-based cross-sectional study.

BACKGROUND: Regular utilization of maternal health care services reduces maternal morbidity and mortality. This study assessed the maternal health care seeking behavior and associated factors of reproductive age women in rural villages of Haramaya district, East Ethiopia. METHODS: Community based cross sectional study supplemented with qualitative data was conducted in Haramaya district from November 15 to Decemeber 30, 2015. A total of 561 women in reproductive age group and who gave birth in the last 2 years were randomly included. Bivariate and multivariate logistic regressions model was used to identify the associated factors. Odds ratios with 95% CI were used to measure the strength of association. RESULT: Maternal health care service seeking of women was found as; antenatal care 74.3% (95% CI; 72.5, 76.14), attending institutional delivery 28.7% (95% CI; 26.8, 30.6) and postnatal care 22.6% (95% CI; 20.84, 24.36). Knowledge of pregnancy complications, Educational status, and religion of women were found to be significantly associated with antenatal health care, delivery and postnatal health care service seeking behaviours triangulated with individual, institutional and socio-cultural qualitative data. CONCLUSION: The maternal health care service seeking behavior of women in the study area was low. Educational status of the women, birth order and knowledge about pregnancy complications were the major factors associated with maternal health care service seeking behavior Focused health education with kind and supportive health care provider counseling will improve the maternal health care seeking behaviors of women.

Seroprevalence of Toxoplasma gondii and associated risk factors among HIV-infected women within reproductive age group at Mizan Aman General Hospital, Southwest Ethiopia: a cross sectional study.

BACKGROUND: Toxoplasmosis is serious in the case of immune suppression and prenatal transmission. In immunocompromised hosts, it is manifested primarily as a life-threatening condition, toxoplasmic encephalitis. Congenital toxoplasmosis results in abortion or congenitally acquired disorders which primarily affect the central nervous system. This study assessed seroprevalence of Toxoplasma gondii (T. gondii) infection and associated factors among HIV-infected women within the reproductive age group (18-49 years) at Mizan Aman General Hospital, Southwest Ethiopia. An institution based cross-sectional study was conducted from February 01 to May 30, 2015. Systematic random sampling technique was employed for participant selection. Enzyme linked immuno sorbent assay was used to test for T. gondii from venous blood specimens. Participants were interviewed using structured questionnaire for different variables. Descriptive statistics, binary and multivariable logistic regression analyses were performed during data analysis. P value of less than 0.05 was considered statistically significant. RESULTS: A total of 270 HIV-infected women within the reproductive age group were included in the study. Mean age of the respondents was 31 years (SD = ±6.5). Of the total study participants, 255 (94.4%), 95% CI (91.6, 97.2%) were found to be seropositive for T. gondii anti-immunoglobulin G (IgG) antibody, and 6 (2.2%), 95% CI (1.3, 3.1%) for anti-immunoglobulin M (IgM). All the anti-IgM positive samples were also positive for IgG. Multivariate analysis showed that; age within 28-37 years (Adjusted Odds Ratio [AOR] 2.58, 95% CI 1.01, 6.60), level of education with unable or only able to read and write (AOR = 4.46, 95% CI 1.20, 16.60), and substance abuse (AOR = 4.49, 95 CI 1.60, 12.55) were significantly associated with seropositivity of T. gondii infection. CONCLUSIONS: Seroprevalence of toxoplasmosis among the HIV-infected women in the childbearing age group in Mizan Aman was high. Age, educational status and drug addiction were identified as factors associated with T. gondii infection. Education of HIV-infected women about the transmission and prevention methods of T. gondii infection is important. Besides, studies on incidence of toxoplasmosis in newborns and infants are recommended.