The Burden of Snakebite in Rural Communities in Kenya: A Household Survey

Dermonecrosis caused by a spitting cobra snakebite results from toxin potentiation and is prevented by the repurposed drug varespladib

Snakebite envenoming is a neglected tropical disease that causes substantial mortality and morbidity globally. The venom of African spitting cobras often causes permanent injury via tissue-destructive dermonecrosis at the bite site, which is ineffectively treated by current antivenoms. To address this therapeutic gap, we identified the etiological venom toxins in Naja nigricollis venom responsible for causing local dermonecrosis. While cytotoxic three-finger toxins were primarily responsible for causing spitting cobra cytotoxicity in cultured keratinocytes, their potentiation by phospholipases A2 toxins was essential to cause dermonecrosis in vivo. This evidence of probable toxin synergism suggests that a single toxin-family inhibiting drug could prevent local envenoming. We show that local injection with the repurposed phospholipase A2-inhibiting drug varespladib significantly prevents local tissue damage caused by several spitting cobra venoms in murine models of envenoming. Our findings therefore provide a therapeutic strategy that may effectively prevent life-changing morbidity caused by snakebite in rural Africa.

Revolutionizing snakebite care with novel antivenoms: Breakthroughs and barriers

Snakebite envenoming (SBE) is a global public health concern, primarily due to the lack of effective antivenom for treating snakebites inflicted by medically significant venomous snakes prevalent across various geographic locations. The rising demand for safe, cost-effective, and potent snakebite treatments highlights the urgent need to develop alternative therapeutics targeting relevant toxins. This development could provide promising discoveries to create novel recombinant solutions, leveraging human monoclonal antibodies, synthetic peptides and nanobodies. Such technologies as recombinant DNA, peptide and epitope mapping phage display etc) have the potential to exceed the traditional use of equine polyclonal antibodies, which have long been used in antivenom production. Recombinant antivenom can be engineered to target certain toxins that play a critical role in snakebite pathology. This approach has the potential to produce antivenom with improved efficacy and safety profiles. However, there are limitations and challenges associated with these emerging technologies. Therefore, identifying the limitations is critical for overcoming the associated challenges and optimizing the development of recombinant antivenoms. This review is aimed at presenting a thorough overview of diverse technologies used in the development of recombinant antivenom, emphasizing their limitations and offering insights into prospects for advancing recombinant antivenoms.

Conducting epidemiological studies on snakebite in nomadic populations: A methodological paper

INTRODUCTION

Research on snakebite has mostly been conducted on settled populations and current risk factors and potential interventions are therefore most suited for these populations. There is limited epidemiological data on mobile and nomadic populations, who may have a higher risk of snakebite.

METHODS AND RESULTS

We conducted a scoping review to gather evidence on survey methods used in nomadic populations and compared them with contemporary survey methods used for snakebite research. Only 16 (10.5%) of 154 articles reportedly conducted on pastoralist nomadic populations actually involved mobile pastoralists. All articles describing snakebite surveys (n = 18) used multistage cluster designs on population census sampling frames, which would not be appropriate for nomadic populations. We used geospatial techniques and open-source high-resolution satellite images to create a digital sampling frame of 50,707 households and used a multistage sampling strategy to survey nomadic and semi-nomadic populations in Samburu County, Kenya. From a sample of 900 geo-located households, we correctly identified and collected data from 573 (65.4%) households, of which 409 were in their original locations and 164 had moved within 5km of their original locations. We randomly sampled 302 (34.6%) households to replace completely abandoned and untraceable households.

CONCLUSION

Highly mobile populations require specific considerations in selecting or creating sampling frames and sampling units for epidemiological research. Snakebite risk has a strong spatial component and using census-based sampling frames would be inappropriate in nomadic populations. We propose using open-source satellite imaging and geographic information systems to improve the conduct of epidemiological research in these populations.

Snakebite epidemiology, outcomes and multi-cluster risk modelling in Eswatini

BACKGROUND

Halving snakebite morbidity and mortality by 2030 requires countries to develop both prevention and treatment strategies. The paucity of data on the global incidence and severity of snakebite envenoming causes challenges in prioritizing and mobilising resources for snakebite prevention and treatment. In line with the World Health Organisation's 2019 Snakebite Strategy, this study sought to investigate Eswatini's snakebite epidemiology and outcomes, and identify the socio-geographical factors associated with snakebite risk.

METHODOLOGY

Programmatic data from the Ministry of Health, Government of Eswatini 2019-2021, was used to assess the epidemiology and outcomes of snakebite in Eswatini. We developed a snake species richness map from the occurrence data of all venomous snakes of medical importance in Eswatini that was subjected to niche modelling. We formulated four risk indices using snake species richness, various geospatial datasets and reported snakebites. A multivariate cluster modelling approach using these indices was developed to estimate risk of snakebite and the outcomes of snakebite in Eswatini.

PRINCIPAL FINDINGS

An average of 466 snakebites was recorded annually in Eswatini. Bites were recorded across the entire country and peaked in the evening during summer months. Two cluster risk maps indicated areas of the country with a high probability of snakebite and a high probability of poor snakebite outcomes. The areas with the highest rate of snakebite risk were primarily in the rural and agricultural regions of the country.

SIGNIFICANCE

These models can be used to inform better snakebite prevention and treatment measures to enable Eswatini to meet the global goal of reducing snakebite morbidity and mortality by 50% by 2030. The supply chain challenges of antivenom affecting southern Africa and the high rates of snakebite identified in our study highlight the need for improved snakebite prevention and treatment tools that can be employed by health care workers stationed at rural, community clinics.

Case fatality rate and burden of snakebite envenoming in children - A systematic review and meta-analysis

Snakebite is a major public health problem with an estimated global burden of 5 million people per annum. Data on snakebite envenoming in children are very limited and is unclear whether there is a significant difference in severity between adults and children. We therefore conducted a meta-analysis of observational studies on snakebite in children to obtain a more precise estimate of case fatality rate (CFR) as well as to explore the differences in outcome between children and adults. Studies from all over the world reported until the end of February 2023 were included. Analysis was conducted consistent with the Meta-analysis of Observational Studies in Epidemiology (MOOSE) criteria. Estimates were obtained from Random Effects Model (REM). Sub-analysis was conducted for studies from sub-Saharan Africa (SSA) to provide estimates for the continent. Adverse outcomes comprising composite endpoints (CE), defined as fatality and or complications, were compared between children and adults in sub-analysis of studies reporting on both groups. The annual burden and fatality of snakebite envenoming were derived based on lifetime prevalence of bite, meta-analysis estimates, and other data inputs. The pooled estimate of the CFR from 35 studies included worldwide was 1.98% [95%CI:1.38-2.58%] while the estimates from 6 studies within SSA was 2.43% (95%CI:0.67-4.20%). The odds of adverse outcomes were 2.52 times higher in children compared to adults. The estimated annual burden was 178,491 cases with 4346 deaths among children in SSA. These estimates compare favorably to those reported in the literature.

Burden and risk factors of snakebite in Mopeia, Mozambique: Leveraging larger malaria trials to generate data of this neglected tropical disease

BACKGROUND

Snakebite is a neglected disease that disproportionally affects the rural poor. There is a dearth of evidence regarding incidence and risk factors in snakebite-endemic countries. Without this basic data, it will be impossible to achieve the target of a 50% reduction of snakebite morbidity and mortality by 2030 as set by the World Health Organization.

METHODS

This was a descriptive analysis nested in a 2021 community-based demographic survey of over 70,000 individuals conducted in Mopeia, Mozambique, in preparation for a cluster randomized trial to test an intervention for malaria. We describe the incidence rate, demographics, socioeconomic indicators and outcomes of snakebite in this population.

FINDINGS

We found the incidence of self-reported snakebite in Mopeia to be 393 bites per 100,000 person-years at risk, with 2% of households affected in the preceding 12 months. Whilst no fatalities were recorded, over 3,000 days of work or school days were lost with an individual household economic impact higher than that of uncomplicated malaria. 1 in 6 of those affected did not fully recover at the time of the study. We found significant relationships between age older than 15, use of firewood for household fuel, and animal possession with snakebite.

CONCLUSIONS

This study exposes higher than expected incidence and burden of snakebite in rural Mozambique. Whilst snakebite elimination in Mozambique seems unattainable today, it remains a preventable disease with manageable sequelae. We have shown that snakebite research is particularly easy to nest in larger studies, making this a practical and cost-effective way of estimating its incidence.

Barriers and enablers of community engagement practices for the prevention of snakebite envenoming in South Asia: A qualitative exploratory study

Snakebite envenoming (SBE) is a grossly neglected tropical disease (NTD) that predominantly affects those living in rural settings in low-and-middle income countries. South Asia currently accounts for the highest global SBE-related mortality, and substantial morbidity rates. To alleviate the high burden in the region, community engagement (CE) is considered to be an integral component for optimizing SBE prevention and control. To better understand existing CE practices for SBE in the region, the experiences of SBE-CE actors concerning the barriers to, and enablers of CE practices were captured through semi-structured interviews. Fifteen key informants from India, Bangladesh and Nepal participated in the study. Important enablers included providing innovative, inclusive and continuous methods and materials, carefully planning of programs, performing monitoring and evaluation, SBE data availability, motivated and trained staff members, good organizational reputations, communication with other SBE-actors, collaborations, and the involvement of the government. Substantial barriers comprised a lack of SBE data, lack of innovative methods and materials for educational purposes, a shortage of human and physical resources, community resistance, untrained health care workers (HCWs), and ineffective traditional healing practices. In order to optimize and sustain SBE-CE practices, context-sensitive, multi-faceted approaches are needed that incorporate all these factors which influence its sustainable implementation.

Pattern and Trends in Adult Hospitalization/Admission and Mortality Among Medical Ward Inpatients at Gadarif Hospital in Eastern Sudan: A Four-Year Retrospective Study

Purpose

Sub-Saharan Africa suffers from a dual impact of communicable (CDs) and non-communicable diseases (NCDs). There is scarce data on causes, trends of admission, and deaths among patients in Sudan. We aimed to determine the causes, trends of admission, and mortality among adult patients admitted to Gadarif Hospital in Eastern Sudan.

Patients and Methods

The medical records of adult patients admitted to Gadarif medical wards from January 2017 to December 2020 were reviewed for age, gender, causes of admission, and outcomes. Multivariate Cox regression analysis was used to analysis factors (age, sex, years, and disease) associated with the mortality.

Results

Of the 7230 patients who were admitted, 2221 (34.7%) were females and 5009 (69.3%) were males. The median age (interquartile range, IQR) was 47.0 (35.0) years. Of these 7230 patients, 3167 (43.8%) and 4063 (56.2%) patients were admitted with CDs and NCDs, respectively. Cardiovascular diseases (18.4%), snakebites (12.9%), and visceral leishmaniasis (12.0%) were the most common causes of admission. The overall in-patient adult deaths were 674 (9.3%). Cardiovascular diseases (22.3%), neurological diseases (16.9%), sepsis (15.9%), renal diseases (13.9%), and snakebites (8.3%) were the most common causes of inpatient mortality. Malignancy (20.7%), sepsis (20.9%), neurological diseases (17.4%), and cardiovascular diseases (13.8%) comprised the highest case fatality rates among the admitted patients. Using a Cox regression model (adjusted), age (adjusted hazard ratio = 1.02, 95% confidence interval = 1.01‒1.03) was associated with increased mortality hazard. However, the gender and years of admission were not associated with increased mortality hazard.

Conclusion

Admissions and mortality rates for CDs and NCDs are high compared with other African countries. Preventive measures are required to avert the high burden of these diseases. Health care systems in Sudan need to be prepared to deal with the dual burden of the diseases.

Availability, affordability and stock-outs of commodities for the treatment of snakebite in Kenya

BACKGROUND

Annually, about 2.7 million snakebite envenomings occur globally. Alongside antivenom, patients usually require additional care to treat envenoming symptoms and antivenom side effects. Efforts are underway to improve snakebite care, but evidence from the ground to inform this is scarce. This study, therefore, investigated the availability, affordability, and stock-outs of antivenom and commodities for supportive snakebite care in health facilities across Kenya.

METHODOLOGY/PRINCIPAL FINDINGS

This study used an adaptation of the standardised World Health Organization (WHO)/Health Action International methodology. Data on commodity availability, prices and stock-outs were collected in July-August 2020 from public (n = 85), private (n = 36), and private not-for-profit (n = 12) facilities in Kenya. Stock-outs were measured retrospectively for a twelve-month period, enabling a comparison of a pre-COVID-19 period to stock-outs during COVID-19. Affordability was calculated using the wage of a lowest-paid government worker (LPGW) and the impoverishment approach. Accessibility was assessed combining the WHO availability target (≥80%) and LPGW affordability (<1 day's wage) measures. Overall availability of snakebite commodities was low (43.0%). Antivenom was available at 44.7% of public- and 19.4% of private facilities. Stock-outs of any snakebite commodity were common in the public- (18.6%) and private (11.7%) sectors, and had worsened during COVID-19 (10.6% versus 17.0% public sector, 8.4% versus 11.7% private sector). Affordability was not an issue in the public sector, while in the private sector the median cost of one vial of antivenom was 14.4 days' wage for an LPGW. Five commodities in the public sector and two in the private sector were deemed accessible.

CONCLUSIONS

Access to snakebite care is problematic in Kenya and seemed to have worsened during COVID-19. To improve access, efforts should focus on ensuring availability at both lower- and higher-level facilities, and improving the supply chain to reduce stock-outs. Including antivenom into Universal Health Coverage benefits packages would further facilitate accessibility.