Challenges associated with the availability, accessibility, and use of antivenoms for treating snakebite envenoming in Ghana: A MaxDiff experiment design

Successful snakebite envenoming (SBE) treatment requires safe, effective, and quality-assured antivenom products specifically tailored to combat endemic venomous snake species. This study aims to identify the challenges associated with the availability, accessibility, and use of antivenoms for treating SBE. The data for this study were obtained from a cross-sectional study involving healthcare workers from two districts (namely Afram Plains North and Afram Plains South) in the Eastern Region of Ghana. Through the MaxDiff design methodology, we quantify the challenges associated with the availability, accessibility, and use of antivenoms. Responses from a simple random sample of 203 healthcare workers were included in this study. Participants identified the high cost of antivenoms as the most challenging factor that limits the availability, accessibility, and use of antivenoms for treating SBE. Other important challenges were the lack of access to effective antivenoms in remote areas when needed and the increased use of unorthodox and harmful practices, followed by resort to unorthodox and harmful practices and the lack of effective antivenoms to address envenoming from local species in some instances. However, poor outcomes from using substandard antivenoms, stock-outs, inadequate number of manufacturers, and the resort to substandard, cheap, and harmful antivenoms were traded off. Also, poor utilization of antivenoms, suboptimal utilization of antivenoms (low quality, under-dose), use of ineffective, substandard antivenoms, and flooding of the market with products that have not been evaluated thoroughly were underscored. Our findings provide essential data to guide discussions on barriers to the availability, accessibility, and use of antivenoms for treating SBE to improve the supply of antivenoms, enhance the effectiveness of snakebite treatment, and improve patient care quality in Ghana. Multi-component strategies are needed to address the challenges identified, such as intensified advocacy, ongoing education and community engagement, healthcare worker training, and leveraging institutional and governance structures.

The Colombian bushmasters Lachesis acrochorda (García, 1896) and Lachesis muta (Linnaeus, 1766): Snake species, venoms, envenomation, and its management

In Colombia, there are two species of bushmaster snakes, Lachesis acrochorda, which is distributed mainly in the west of the country (in the Choco region), and Lachesis muta in the southeast (in the Amazon and Orinoquia region), whose presence has been reduced due to the destruction of their habitats. Captive maintenance is challenging, making it difficult to obtain their venom for study and antivenom manufacturing. They are the largest vipers in the world. The occurrence of human envenomation is quite rare, but when it occurs, it is associated with high mortality. Bushmaster venom is necrotizing, hemorrhagic, myotoxic, hemolytic, and cardiovascular depressant. Due to the presence of bradycardia, hypotension, emesis, and diarrhea in some patients (Lachesis syndrome), the possibility of a vagal or cholinergic effect is raised. The treatment of envenomation is hindered by the scarcity of antivenom and the need to use high doses. A review of the most relevant biological and medical aspects of bushmaster snakes is presented, mainly for those occurring in Colombia, to facilitate their recognition and raise awareness about the need for special attention to improve their conservation and advance scientific knowledge, in particular, about their venom.

Preliminary assessment of antivenom availability and management in the public health system of Costa Rica: An analysis based on a survey to pharmacists in public health facilities

Availability and accessibility of safe and effective antivenoms are key elements for the successful treatment of snakebite envenoming (SBE). This study provides a preliminary analysis on the way antivenoms are managed by the public health system in Costa Rica and on the role played by pharmacists in the overall management of antivenoms. This was an observational, cross-sectional study based on an online survey sent to pharmacists working at Caja Costarricense de Seguro Social (Costa Rican Social Security System; CCSS) in different locations in Costa Rica. Characteristics and location of health facilities, as well as antivenom availability and management details, were analyzed. Responses from a total of 96 pharmacists, corresponding to 55 different healthcare facilities, were included in this study. Most respondents worked at pharmacies located in urban communities (69.0%) and in the secondary level of care, which includes clinics, and regional and peripheral hospitals (55.2%). Overall, participants reported antivenom availability at all levels of care and in centers having various operating schedules, although they were not available in some facilities in regions where SBE is uncommon or do not attend SBE cases because of the proximity of more complex health centers. On average, the stocks of anticoral and polyvalent antivenoms per health facility were compatible with the dose of antivenom required for treating a SBE case. More than half of participants reported knowing the availability of protocols for the management of SBE and the correct use of antivenom at their healthcare facilities. Of the total respondents, 49% agreed on possessing all the resources needed for the correct management of these medicines at their facilities, and 65.6% indicated that they know the procedures for antivenom storage and management. Our findings provide a first description of the availability of antivenoms in the public health system of Costa Rica, including the primary care level. Results also underscore the perceived role of participating pharmacists in the management of these life-saving drugs and the need to improve their knowledge on this topic.

Assessment of neutralization of Micrurus venoms with a blend of anti-Micrurus tener and anti-ScNtx antibodies

BACKGROUND

Micrurus venoms contain two main groups of toxic protein components: short-chain α-neurotoxins (SNtx) and phospholipases type A₂ (PLA₂). In North America, generally, the Micrurus venoms have low abundance of SNtx compared to that of PLA₂s; however, both are highly toxic to mammals, and consequently both can play a major role in the envenomation processes. Concerning the commercial horse-derived antivenoms against Micrurus from the North America region, they contain a relatively large amount of antibodies against PLA₂s, and a low content of antibodies against short chain α-neurotoxins. This is mainly due to the lower relative abundance of SNtxs, and also to its poor immunogenicity due to their size and nature. Hence, Micrurus antivenoms made in North America usually present low neutralizing capacity towards Micrurus venoms whose lethality depend largely on short chain α-neurotoxins, such as South American Micrurus species.

METHODS

Horses were hyperimmunized with either the venom of M. tener (PLA₂-predominant) or a recombinant short-chain consensus α-neurotoxin (ScNtx). Then, the combination of the two monospecific horse antibodies (anti-M. tener and anti-ScNtx) was used to test their efficacy against eleven Micrurus venoms.

RESULTS

The blend of anti-M. tener and anti-ScNtx antibodies had a better capacity to neutralize the lethality of diverse species from North, Central and South American Micrurus venoms. The antibodies combination neutralized both the ScNtx and ten out of eleven Micrurus venom tested, and particularly, it neutralized the venoms of M. distans and M. laticollaris that were neither neutralized by monospecific anti-M. tener nor anti-ScNtx.

CONCLUSIONS

These results provide a proof-of-principle for using recombinant immunogens to enrich poor or even non-neutralizing antisera against elapid venoms containing short chain α-neurotoxins to develop antivenoms with higher effectiveness and broader neutralizing capacity.