Shortcomings in snake bite management in rural Cameroon: a case report

Dimethyl ester of bilirubin ameliorates Naja naja snake venom-induced lung toxicity in mice via inhibiting NLRP3 inflammasome and MAPKs activation

Naja naja snake bite causes thousands of deaths worldwide in a year. N. naja envenomed victims exhibit both local and systemic reactions that potentially lead to death. In clinical practice, pulmonary complications in N. naja envenomation are commonly encountered. However, the molecular mechanisms underlying N. naja venom-induced lung toxicity remain unknown. Here, we reasoned that N. naja venom-induced lung toxicity is prompted by NLRP3 inflammasome and MAPKs activation in mice. Treatment with dimethyl ester of bilirubin (BD1), significantly inhibited the N. naja venom-induced activation of NLRP3 inflammasome and MAPKs both in vivo and in vitro (p < 0.05). Further, BD1 reduced N. naja venom-induced recruitment of inflammatory cells, and hemorrhage in the lung toxicity examined by histopathology. BD1 also diminished N. naja venom-induced local toxicities in paw edema and myotoxicity in mice. Furthermore, BD1 was able to enhance the survival time against N. naja venom-induced mortality in mice. In conclusion, the present data showed that BD1 alleviated N. naja venom-induced lung toxicity by inhibiting NLRP3 inflammasome and MAPKs activation. Small molecule inhibitors that intervene in venom-induced toxicities may have therapeutic applications complementing anti-snake venom.

[Incidence of snakebites in rural communities living in the Paoua savannah and Mbaïki forest areas in Central African Republic]

Introduction

Snakebite is one of the most deadly neglected tropical diseases in Africa with more than 20,000 deaths reported each year. According to recent data from hospital in Central African Republic studies, the Paoua health district reports between 300 and 400 cases of ophidian envenomation each year. However, no epidemiological study on snakebites has been conducted at national level, nor a control strategy developed. The objective of this study is to describe the epidemiological aspects of snakebites in two rural communities, one located in savannah zone and the other in forest zone (both secondary and primary forest) in order to ensure adequate management of snakebites in these regions.

Method

Prospective community-based study in two health districts in the Central African Republic, the health district of Paoua in savannah area and the health district of Mbaïki in forest area, from December 2019 to January 2021. Snakebites were investigated in the community by selected trained people in charge of reporting data regarding all known cases of snakebites occurring during the study period. The data were actively notified either by health personal or community health workers in order to determine the circumstances and severity of the bite, its management and the clinical course in case of envenomation.

Results

A total of 412 snakebite cases were recorded during the study period, of which 198 cases occurred in the rural community of the forest zone and 214 in the community of the savannah zone. Case fatality rate was 5% in the forest zone and 1% in the savanna zone. The incidence rate of snakebite was significantly higher in savannah children compared to those in the forest (98/100,000 vs. 25.1/100,000; p<0.00001) while this incidence rate was significantly lower from age 45 onwards in the savannah area compared to the forest area (167/100,000 vs. 200/100,000; p=0.02). The case fatality rate of children and adults up to 44 years of age appeared to be significantly higher in the forest zone (7 deaths vs 1 death). Snakebites occurred significantly more frequently during field activities in the savannah zone than in the forest zone (51% vs 26%; p<0.0001). The symptomatology of bites was dominated by edema of the bitten limb and bleeding in the two study areas, compatible with cytotoxic and hemorrhagic syndromes due to viper bites.

Conclusion

With an incidence rate of more than 160 cases per 100,000 inhabitants in the active population aged 15-44 years in rural communities of the forest and savannah zone, snakebites remain a public health problem in Central African Republic. A study on the toxicity of snakebites in Central African Republic is recommended. Besides, it is urgent to make anti-venomous serums available in health facilities in order to reduce the mortality related to the envenomation.

Protein Identification of Venoms of the African Spitting Cobras, Naja mossambica and Naja nigricincta nigricincta

Cobra snakes, including Naja mossambica and Naja nigricincta nigricincta, are one of the major groups of snakes responsible for snakebites in southern Africa, producing significant cytotoxicity and tissue damage. The venom of N. mossambica has been briefly characterised, but that of N. n. nigricincta is not reported. The current study identifies the venom proteins of N. mossambica and N. n. nigricincta. This is achieved using sodium dodecyl sulphate (SDS)-polyacrylamide gel eletrophroresis (PAGE), followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Most of the proteins were less than 17 kDa in both snakes. N. mossambica was found to have 75 proteins in total (from 16 protein families), whereas N.n. nigricincta had 73 (from 16 protein families). Of these identified proteins, 57 were common in both snakes. The proteins identified belonged to various families, including the three-finger toxins (3FTx), Cysteine-rich secretory proteins (CRiSP), Phospholipase A2 (PLA₂) and Venom metalloproteinase M12B (SVMP). The current study contributes to the profile knowledge of snake venom compositions, which is of fundamental value in understanding the proteins that play a major role in envenomation.

Epidemiology, ecology and human perceptions of snakebites in a savanna community of northern Ghana

BACKGROUND

Worldwide, snakebite envenomations total ~2.7 million reported cases annually with ~100,000 fatalities. Since 2009, snakebite envenomation has intermittently been classified as a very important 'neglected tropical disease' by the World Health Organisation. Despite this emerging awareness, limited efforts have been geared towards addressing the serious public health implications of snakebites, particularly in sub-Saharan Africa, where baseline epidemiological and ecological data remain incomplete. Due to poverty as well as limited infrastructure and public health facilities, people in rural Africa, including Ghana, often have no other choice than to seek treatment from traditional medical practitioners (TMPs). The African 'snakebite crisis' is highlighted here using regionally representative complementary data from a community-based epidemiological and ecological study in the savanna zone of northern Ghana.

METHODOLOGY AND FINDINGS

Our baseline study involved two data collection methods in the Savelugu-Nanton District (in 2019 the district was separated into Savelugu and Nanton districts) in northern Ghana, comprising a cross-sectional study of 1,000 residents and 24 TMPs between December 2008 and May 2009. Semi-structured interviews, as well as collection of retrospective snakebite and concurrent rainfall records from the Savelugu-Nanton District Hospital and Ghana Meteorological Authority respectively over 10-years (1999-2008) were used in the study. Variables tested included demography, human activity patterns, seasonality, snake ecology and clinical reports. Complementary data showed higher snakebite prevalence during the rainy season, and a hump-shaped correlation between rainfall intensity and snakebite incidences. Almost 6% of respondents had experienced a personal snakebite, whereas ~60% of respondents had witnessed a total of 799 snakebite cases. Out of a total of 857 reported snakebite cases, 24 (~2.8%) died. The highest snakebite prevalence was recorded for males in the age group 15-44 years during farming activities, with most bites occurring in the leg/foot region. The highest snakebite rate was within farmlands, most severe bites frequently caused by the Carpet viper (Echis ocellatus).

CONCLUSION

The relatively high community-based prevalence of ~6%, and case fatality ratio of ~3%, indicate that snakebites represent an important public health risk in northern Ghana. Based on the high number of respondents and long recording period, we believe these data truly reflect the general situation in the rural northern savanna zone of Ghana and West Africa at large. We recommend increased efforts from both local and international health authorities to address the current snakebite health crisis generally compromising livelihoods and productivity of rural farming communities in West Africa.

Severe Viperidae envenomation complicated by a state of shock, acute kidney injury, and gangrene presenting late at the emergency department: a case report

Background

Snake envenomation is an underestimated pathology in sub-Saharan Africa associated with severe emergencies, and even death in case of late presentation. We herein present a case of severe envenomation managed at the surgical emergency department of the Yaoundé Central Hospital.

Case presentation

We report a case of a 47-year-old female farmer with no relevant past history who sustained a snakebite by an Echis occellatus viper during an agricultural activity. Her initial management consisted in visiting a traditional healer who administered her some herbal remedies orally and applied a white balm on the affected limb. Due to progressive deterioration of her condition, she was rushed to our surgical department where she arrived 20 h after the snakebite incident. On admission she presented in a state of shock (suggestive of an anaphylactic shock), coagulopathy, renal impairment, and gangrene of the entire right upper limb. Emergency management consisted of fluid resuscitation, repeated boluses of adrenaline, a total of three vials of polyvalent anti-venom sera, promethazine, analgesics, corticosteroids, and administration of fresh frozen plasma. Within four hours of emergency department hospitalisation she developped signs of sepsis and persistent hypotension refractory to fluid resuscitation, suggestive of an associated septic shock. Management pursued with antiobiotherapy and administration of noradrenaline through an electric pump syringe to achieve a mean arterial blood pressure above 65 mmHg. The patient deceased at the 10th hour of hospitalisation in a state of circulatory collapse unresponsive to vasopressors, coagulopathy, renal failure, sepsis and gangrene of the right forearm.

Conclusion

The authors highlight this unusual presentation but equally pinpoint how late presentation to the emergency department, harmful tradition practices, poverty and cultural beliefs can adversely affect the prognosis of snakebite in our setting.

Community-based audits of snake envenomations in a resource-challenged setting of Cameroon: case series

Background

Snakebites are a major cause of mortality and morbidity worldwide with the highest mortality burden in poor rural areas of sub-Saharan Africa. Inadequate surveillance systems result in loss of morbidity and mortality data in these settings. Although rarely reported in these resource-constraint environments, community-based audits are recognised pivotal tools which could help update existing data and indicate key public health interventions to curb snakebite-related mortality. Herein, we present two cases of snakebite-related deaths in a rural Cameroonian community.

Case presentations

The first case was a 3-year-old female who presented at a primary care health centre and was later referred due to absence of antivenom serum (AVS). However, she had an early fatal outcome before getting to the referral hospital. The second case was an 80-year-old traditional healer who got bitten while attempting to kill a snake. He died before hospital presentation.

Conclusion

Community-based audits help identify key intervention points to curb snakebite mortality in high-risk rural areas like ours. From our audits, we note a remarkable absence of affordable AVS in rural health facilities in Cameroon. We recommend frequent community health education sessions on preventing snakebites; continuous training modules for health personnel from high-risk areas; training traditional healers on the importance of AVS in managing cases of snakebite envenoming, and the need for timely hospital presentation; and setting up context-specific approaches to rapidly transport snakebite victims to hospitals.