Snakebites in “Invisible Populations”: A cross-sectional survey in riverine populations in the remote western Brazilian Amazon

In the Brazilian Amazon, long distances, low healthcare coverage, common use of ineffective or deleterious self-care practices, and resistance to seeking medical assistance have an impact on access to antivenom treatment. This study aimed to estimate snakebite underreporting, and analyze barriers that prevent victims from obtaining healthcare in communities located in 15 municipalities on the banks of the Solimões, Juruá and Purus Rivers, in the remote Western Brazilian Amazon. Information on the participants’ demographics, previous snakebites, access to healthcare, time taken to reach medical assistance, use of self-care practices, and the reason for not accessing healthcare were collected through semi-structured interviews. In the case of deaths, information was collected by interviewing parents, relatives or acquaintances. A total of 172 participants who reported having suffered snakebites during their lifetime were interviewed. A total of 73 different treatment procedures was reported by 65.1% of the participants. Participants living in different river basins share few self-care procedures that use traditional medicine, and 91 (52.9%) participants reported that they had access to healthcare. Living in communities along the Juruá River [OR = 12.6 (95% CI = 3.2–49.7; p<0.001)] and the use of traditional medicine [OR = 11.6 (95% CI = 3.4–39.8; p<0.001)] were variables that were independently associated to the lack of access to healthcare. The main reasons for not accessing healthcare were the pprioritization of traditional treatments (70.4%), and the failure to recognize the situation as being potentially severe (50.6%). Four deaths from complications arising from the snakebite were reported, and three of these were from communities on the banks of the Juruá River. Only one of these received medical assistance. We found an unexpectedly high underreporting of snakebite cases and associated deaths. Snakebite victims utilized three main different healing systems: 1) self-care using miscellaneous techniques; 2) official medical healthcare generally combined with traditional practices; and 3) self-care using traditional practices combined with Western medicines. To mitigate snakebite burden in the Brazilian Amazon, an innovative intervention that would optimize timely delivery of care, including antivenom distribution among existing community healthcare centers, is needed.     

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

BackgroundAnnually, 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 findingsThis 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.ConclusionsAccess 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.     

Time delays in treatment of snakebite patients in rural Sri Lanka and the need for rapid diagnostic tests

Delays in treatment seeking and antivenom administration remain problematic for snake envenoming. We aimed to describe the treatment seeking pattern and delays in admission to hospital and administration of antivenom in a cohort of authenticated snakebite patients. Adults (> 16 years), who presented with a confirmed snakebite from August 2013 to October 2014 were recruited from Anuradhapura Hospital. Demographic data, information on the circumstances of the bite, first aid, health-seeking behaviour, hospital admission, clinical features, outcomes and antivenom treatment were documented prospectively. There were 742 snakebite patients [median age: 40 years (IQR:27–51; males: 476 (64%)]. One hundred and five (14%) patients intentionally delayed treatment by a median of 45min (IQR:20-120min). Antivenom was administered a median of 230min (IQR:180–360min) post-bite, which didn’t differ between directly admitted and transferred patients; 21 (8%) receiving antivenom within 2h and 141 (55%) within 4h of the bite. However, transferred patients received antivenom sooner after admission to Anuradhapura hospital than those directly admitted (60min [IQR:30-120min] versus 120min [IQR:52-265min; p<0.0001]). A significantly greater proportion of transferred patients had features of systemic envenoming on admission compared to those directly admitted (166/212 [78%] versus 5/43 [12%]; p<0.0001), and had positive clotting tests on admission (123/212 [58%] versus 10/43 [23%]; p<0.0001). Sri Lankan snakebite patients present early to hospital, but there remains a delay until antivenom administration. This delay reflects a delay in the appearance of observable or measurable features of envenoming and a lack of reliable early diagnostic tests. Improved early antivenom treatment will require reliable, rapid diagnostics for systemic envenoming.     

Surveillance,health promotion and control of Chagas disease in the Amazon Region - Medical attention in the Brazilian Amazon Region: a proposal

We refer to Oswaldo Cruz''s reports dating from 1913 about the necessities of a healthcare system for the Brazilian Amazon Region and about the journey of Carlos Chagas to 27 locations in this region and the measures that would need to be adopted. We discuss the risks of endemicity of Chagas disease in the Amazon Region. We recommend that epidemiological surveillance of Chagas disease in the Brazilian Amazon Region and Pan-Amazon region should be implemented through continuous monitoring of the human population that lives in the area, their housing, the environment and the presence of triatomines. The monitoring should be performed with periodic seroepidemiological surveys, semi-annual visits to homes by health agents and the training of malaria microscopists and healthcare technicians to identify Trypanosoma cruzi from patients'' samples and T. cruzi infection rates among the triatomines caught. We recommend health promotion and control of Chagas disease through public health policies, especially through sanitary education regarding the risk factors for Chagas disease. Finally, we propose a healthcare system through base hospitals, intermediate-level units in the areas of the Brazilian Amazon Region and air transportation, considering the distances to be covered for medical care.     

Treatment outcomes among snakebite patients in north-west Ethiopia—A retrospective analysis

BackgroundMillions of people are bitten by venomous snakes annually, causing high mortality and disability, but the true burden of this neglected health issue remains unknown. Since 2015, Médecins Sans Frontières has been treating snakebite patients in a field hospital in north-west Ethiopia. Due to the poor market situation for effective and safe antivenoms for Sub-Saharan Africa, preferred antivenom was not always available, forcing changes in choice of antivenom used. This study describes treatment outcomes and the effectiveness and safety of different antivenoms used.Methodology / Principal findingsThis retrospective observational study included 781 snakebite patients presenting at the field hospital between 2015 and 2019. Adjusted odds ratios, 95%-CI and p-values were used to compare the treatment outcome of patients treated with Fav-Afrique (n = 149), VacSera (n = 164), and EchiTAb-PLUS-ICP (n = 156) antivenom, and to identify the risk of adverse reactions for each antivenom. Whereas only incidental snakebite cases presented before 2015, after treatment was made available, cases rapidly increased to 1,431 in 2019. Envenomation was mainly attributed to North East African saw-scaled viper (Echis pyramidum) and puff adder (Bitis arietans). Patients treated with VacSera antivenom showed lower chance of uncomplicated treatment outcome (74.4%) compared to Fav-Afrique (93.2%) and EchiTAb-PLUS-ICP (90.4%). VacSera and EchiTAb-PLUS-ICP were associated with 16- and 6-fold adjusted odds of treatment reaction compared to Fav-Afrique, respectively, and VacSera was weakly associated with higher odds of death.Conclusions / SignificanceSnakebite frequency is grossly underreported unless treatment options are available. Although EchiTAb-PLUS-ICP showed favorable outcomes in this retrospective analysis, prospective randomized trials are needed to evaluate the effectiveness and safety of the most promising antivenoms for Sub-Saharan Africa. Structural investment in sustained production and supply of antivenom is urgently needed.     

Novel transdisciplinary methodology for cross-sectional analysis of snakebite epidemiology at national scale

BackgroundWorldwide, it is estimated that snakes bite 4.5–5.4 million people annually, 2.7 million of which are envenomed, and 81,000–138,000 die. The World Health Organization reported these estimates and recognized the scarcity of large-scale, community-based, epidemiological data. In this context, we developed the “Snake-Byte” project that aims at (i) quantifying and mapping the impact of snakebite on human and animal health, and on livelihoods, (ii) developing predictive models for medical, ecological and economic indicators, and (iii) analyzing geographic accessibility to healthcare. This paper exclusively describes the methodology we developed to collect large-scale primary data on snakebite in humans and animals in two hyper-endemic countries, Cameroon and Nepal.Methodology/Principal findingsWe compared available methods on snakebite epidemiology and on multi-cluster survey development. Then, in line with those findings, we developed an original study methodology based on a multi-cluster random survey, enhanced by geospatial, One Health, and health economics components. Using a minimum hypothesized snakebite national incidence of 100/100,000/year and optimizing design effect, confidence level, and non-response margin, we calculated a sample of 61,000 people per country. This represented 11,700 households in Cameroon and 13,800 in Nepal. The random selection with probability proportional to size generated 250 clusters from all Cameroonian regions and all Nepalese Terai districts. Our household selection methodology combined spatial randomization and selection via high-resolution satellite images. After ethical approval in Switerland (CCER), Nepal (BPKIHS), and Cameroon (CNERSH), and informed written consent, our e-questionnaires included geolocated baseline demographic and socio-economic characteristics, snakebite clinical features and outcomes, healthcare expenditure, animal ownership, animal outcomes, snake identification, and service accessibility.Conclusions/SignificanceThis novel transdisciplinary survey methodology was subsequently used to collect countrywide snakebite envenoming data in Nepal and Cameroon. District-level incidence data should help health authorities to channel antivenom and healthcare allocation. This methodology, or parts thereof, could be easily adapted to other countries and to other Neglected Tropical Diseases.     

Health and economic burden estimates of snakebite management upon health facilities in three regions of southern Burkina Faso

BackgroundSnakebite has become better recognized as a significant cause of death and disability in Sub-Saharan Africa, but the health economic consequences to victims and health infrastructures serving them remain poorly understood. This information gap is important as it provides an evidence-base guiding national and international health policy decision making on the most cost-effective interventions to better manage snakebite. Here, we assessed hospital-based data to estimate the health economic burden of snakebite in three regions of Burkina Faso (Centre-Ouest, Hauts Bassins and Sud-Ouest).MethodologyPrimary data of snakebite victims admitted to regional and district health facilities (eg, number of admissions, mortality, hospital bed days occupied) was collected in three regions over 17 months in 2013/14. The health burden of snakebite was assessed using Disability-Adjusted Life Years (DALYs) calculations based upon hospitalisation, mortality and disability data from admitted patients amongst other inputs from secondary sources (eg, populations, life-expectancy and age-weighting constants). An activity-based costing approach to determine the direct cost of snake envenoming included unit costs of clinical staff wages, antivenom, supportive care and equipment extracted from context-relevant literature.FindingsThe 10,165 snakebite victims admitted to hospital occupied 28,164 hospital bed days over 17 months. The annual rate of hospitalisation and mortality of admitted snakebite victims was 173 and 1.39/100,000 population, respectively. The estimated annual (i) DALYs lost was 2,153 (0.52/1,000) and (ii) cost to hospitals was USD 506,413 (USD 49/hospitalisation) in these three regions of Burkina Faso. These costs appeared to be influenced by the number of patients receiving antivenom (10.90% in total) in each area (highest in Sud-Ouest) and the type of health facility.ConclusionThe economic burden of snake envenoming is primarily shouldered by the rural health centres closest to snakebite victims–facilities that are typically least well equipped or resourced to manage this burden. Our study highlights the need for more research in other regions/countries to demonstrate the burden of snakebite and the socioeconomic benefits of its management. This evidence can guide the most cost-effective intervention from government and development partners to meet the snakebite-management needs of rural communities and their health centres.     

Bat Species Composition in Three Localities in the Amazon Basin

We compared the bat species composition of three localities in the Brazilian Amazon: continuous forest and fragments at Alter do Chão, Santarém, an area not previously sampled, and continuous forest in two relatively well studied areas, Manaus and Belém. The number of species captured at each locality varied between 17 and 42. Most species occurred at high abundance in continuous forest in the three localities, but only a subset was common in the fragments at Santarém. The relative abundance of bat species in Santarém is different from other localities sampled in the Amazon Basin and the presence of forest fragments may be the most important factor contributing to this difference. Multidi-mensional scaling ordination of sites based on relative abundance indicated distinct assemblages of bat species in the forest fragments in Santarém, and little differentiation of continuous-forest sites from sites in other localities. Continuous forests at Santarém and near Belém were more similar to each other than to continuous forest near Manaus, indicating the possibility of an east-west gradient in bat communities in the Amazon.     

Analysis of paternal lineages in Brazilian and African populations

The present-day Brazilian population is a consequence of the admixture of various peoples of very different origins, namely, Amerindians, Europeans and Africans. The proportion of each genetic contribution is known to be very heterogeneous throughout the country. The aim of the present study was to compare the male lineages present in two distinct Brazilian populations, as well as to evaluate the African contribution to their male genetic substrate. Thus, two Brazilian population samples from Manaus (State of Amazon) and Ribeirão Preto (State of São Paulo) and three African samples from Guinea Bissau, Angola and Mozambique were typed for a set of nine Y chromosome specific STRs. The data were compared with those from African, Amerindian and European populations. By using Y-STR haplotype information, low genetic distances were found between the Manaus and Ribeirão Preto populations, as well as between these and others from Iberia. Likewise, no significant distances were observed between any of the African samples from Angola, Mozambique and Guinea Bissau. Highly significant Rst values were found between both Brazilian samples and all the African and Amerindian populations. The absence of a significant Sub-Saharan African male component resulting from the slave trade, and the low frequency in Amerindian ancestry Y-lineages in the Manaus and Ribeirão Preto population samples are in accordance with the accentuated gender asymmetry in admixture processes that has been systematically reported in colonial South American populations.     

Cost-effectiveness of Antivenoms for Snakebite Envenoming in Nigeria

Background

Snakebite envenoming is a major public health problem throughout the rural tropics. Antivenom is effective in reducing mortality and remains the mainstay of therapy. This study aimed to determine the cost-effectiveness of using effective antivenoms for Snakebite envenoming in Nigeria.

Methodology

Economic analysis was conducted from a public healthcare system perspective. Estimates of model inputs were obtained from the literature. Incremental Cost Effectiveness Ratios (ICERs) were quantified as deaths and Disability-Adjusted-Life-Years (DALY) averted from antivenom therapy. A decision analytic model was developed and analyzed with the following model base-case parameter estimates: type of snakes causing bites, antivenom effectiveness to prevent death, untreated mortality, risk of Early Adverse Reactions (EAR), mortality risk from EAR, mean age at bite and remaining life expectancy, and disability risk (amputation). End-user costs applied included: costs of diagnosing and monitoring envenoming, antivenom drug cost, supportive care, shipping/freezing antivenom, transportation to-and-from hospital and feeding costs while on admission, management of antivenom EAR and free alternative snakebite care for ineffective antivenom.

Principal Findings

We calculated a cost/death averted of ($2330.16) and cost/DALY averted of $99.61 discounted and $56.88 undiscounted. Varying antivenom effectiveness through the 95% confidence interval from 55% to 86% yield a cost/DALY averted of $137.02 to $86.61 respectively. Similarly, varying the prevalence of envenoming caused by carpet viper from 0% to 96% yield a cost/DALY averted of $254.18 to $78.25 respectively. More effective antivenoms and carpet viper envenoming rather than non-carpet viper envenoming were associated with lower cost/DALY averted.

Conclusions/Significance

Treatment of snakebite envenoming in Nigeria is cost-effective with a cost/death averted of $2330.16 and cost/DALY averted of $99.61 discounted, lower than the country''s gross domestic product per capita of $1555 (2013). Expanding access to effective antivenoms to larger segments of the Nigerian population should be a considered a priority.     

High prevalence of human Torque teno virus in streams crossing the city of Manaus, Brazilian Amazon

Aims:  Torque teno virus (TTV) is a human DNA virus chronically infecting most healthy individuals worldwide and can be transmitted by faecal–oral route. The occurrence of TTV was evaluated in the streams crossing the city of Manaus (Brazilian Amazon) over a 1-year period, four times a year.
Methods and Results:  Fifty-two water samples were collected from 13 different locations. Viruses were concentrated from two litres of water by adsorption to negative membrane filters followed by ultrafiltration. TTV DNA was detected by PCR assays designed to detect all five TTV genomic groups. By conventional PCR, 19/52 (37%) samples were positive. By real-time PCR, TTV DNA could be detected in 48/52 (92%) samples. Viral loads ranged from 1300 to 746 000 genome equivalent per 100 ml of river water. Eleven distinct nucleotide sequences were obtained.
Conclusions:  Our results show the wide distribution and diversity of TTV among Manaus urban micro basins.
Significance and Impact of the Study:  The data presented here may contribute to substantiate TTV as a sensitive indicator of human contamination.     

Pathology-specific experimental antivenoms for haemotoxic snakebite: The impact of immunogen diversity on the in vitro cross-reactivity and in vivo neutralisation of geographically diverse snake venoms

BackgroundSnakebite is a neglected tropical disease that causes high global rates of mortality and morbidity. Although snakebite can cause a variety of pathologies in victims, haemotoxic effects are particularly common and are typically characterised by haemorrhage and/or venom-induced consumption coagulopathy. Antivenoms are the mainstay therapeutic for treating the toxic effects of snakebite, but despite saving thousands of lives annually, these therapies are associated with limited cross-snake species efficacy due to venom variation, which ultimately restricts their therapeutic utility to particular geographical regions.Methodology/Principal findingsIn this study we explored the feasibility of generating globally effective pathology-specific antivenoms to counteract the haemotoxic signs of snakebite envenoming. Two different immunogen mixtures, consisting of seven and twelve haemotoxic venoms sourced from geographically diverse and/or medically important snakes, were used to raise ovine polyclonal antibodies, prior to characterisation of their immunological binding characteristics and in vitro neutralisation profiles against each of the venoms. Despite variability of the immunogen mixtures, both experimental antivenoms exhibited broadly comparable in vitro venom binding and neutralisation profiles against the individual venom immunogens in immunological and functional assays. However, in vivo assessments using a murine preclinical model of antivenom efficacy revealed substantial differences in venom neutralisation. The experimental antivenom generated from the seven venom immunogen mixture outperformed the comparator, by providing protective effects against venom lethality caused by seven of the eight geographically diverse venoms tested, including three distinct venoms that were not used as immunogens to generate this antivenom. These findings suggest that a core set of venom immunogens may be sufficient to stimulate antibodies capable of broadly neutralising a geographically diverse array of haemotoxic snake venoms, and that adding additional venom immunogens may impact negatively on the dose efficacy of the resulting antivenom.Conclusions/SignificanceAlthough selection of appropriate immunogens that encapsulate venom toxin diversity without diluting antivenom potency remains challenging and further optimisation is required, the findings from this pilot study suggest that the generation of pathology-specific antivenoms with global utility is likely to feasible, thereby highlighting their promise as future modular treatments for the world’s tropical snakebite victims.     

Livestock herding and Fulani ethnicity are a combined risk factor for development of early adverse reactions to antivenom treatment: Findings from a cross-sectional study in Nigeria

BackgroundAdverse reactions to antivenom considerably complicate the clinical management of snakebite envenomed patients because it necessitates a temporary suspension of life-saving antivenom, increases costs and can compromise patient outcomes. This study sought to explore the association between cattle-herding occupation and ethnic group and the occurrence of early adverse reactions to antivenom.MethodsThis cross-sectional study was conducted between the 25th April and 11th July 2011 at the Kaltungo General Hospital in north east Nigeria. The exposure variable of cattle-herding occupation showed a strong correlation with the ethnic group variable, thus these were combined into a new variable with three categories (Fulani and herder, either Fulani or herder, and neither Fulani nor herder). The outcome variable was the occurrence of early adverse reactions, defined as any new symptoms occurring within 6 hours of antivenom administration. Odds Ratios were estimated using multivariable logistic regression models controlling for potential confounders.ResultsAmong 231 envenomed snakebite victims, the overall incidence of early adverse reactions was 11.9% (95% confidence intervals: 8.0–16.9%). Patients who were Fulani and herders had a higher incidence of early adverse reactions compared to patients who were neither Fulani nor herders (20% vs 5.7%). After adjusting for age and gender, victims who were Fulani and herders were 5.9 times more likely to have an early adverse reaction, compared to victims who were neither Fulani nor herders (95% CI: 1.88–18.59; p = 0.002).InterpretationTo the best of our knowledge, this is the first study to provide evidence of higher odds of early adverse reactions among patients from a particular occupation and/or ethnic group. We recommend that snake envenomed patients of Fulani origin be especially closely monitored for adverse reactions, that hospitals receiving these patients be appropriately resourced to manage both envenoming and adverse reactions and that premedication with adrenaline should be considered. Our findings provide an argument for speculation on the influence of immunological or lifestyle-related differences on the occurrence of early adverse reactions to antivenom.     

Control of snakebite envenoming: A mathematical modeling study

A mathematical model is designed to assess the impact of some interventional strategies for curtailing the burden of snakebite envenoming in a community. The model is fitted with real data set. Numerical simulations have shown that public health awareness of the susceptible individuals on snakebite preventive measures could reduce the number of envenoming and prevent deaths and disabilities in the population. The simulations further revealed that if at least fifty percent of snakebite envenoming patients receive early treatment with antivenom a substantial number of deaths will be averted. Furthermore, it is shown using optimal control that combining public health awareness and antivenom treatment averts the highest number of snakebite induced deaths and disability adjusted life years in the study area. To choose the best strategy amidst limited resources in the study area, cost effectiveness analysis in terms of incremental cost effectiveness ratio is performed. It has been established that the control efforts of combining public health awareness of the susceptible individuals and antivenom treatment for victims of snakebite envenoming is the most cost effective strategy. Approximately the sum of US$72,548 is needed to avert 117 deaths or 2,739 disability adjusted life years that are recorded within 21 months in the study area. Thus, the combination of these two control strategies is recommended.     

Access to Healthcare,HIV/STI Testing,and Preferred Pre-Exposure Prophylaxis Providers among Men Who Have Sex with Men and Men Who Engage in Street-Based Sex Work in the US

Background

Pre-exposure prophylaxis (PrEP) is a promising strategy for HIV prevention among men who have sex with men (MSM) and men who engage in sex work. But access will require routine HIV testing and contacts with healthcare providers. This study investigated men’s healthcare and HIV testing experiences to inform PrEP implementation.

Methods

We conducted 8 focus groups (n = 38) in 2012 and 56 in-depth qualitative interviews in 2013–14 with male sex workers (MSWs) (n = 31) and other MSM (n = 25) in Providence, RI. MSWs primarily met clients in street-based sex work venues. Facilitators asked participants about access to healthcare and HIV/STI testing, healthcare needs, and preferred PrEP providers.

Results

MSWs primarily accessed care in emergency rooms (ERs), substance use clinics, correctional institutions, and walk-in clinics. Rates of HIV testing were high, but MSWs reported low access to other STI testing, low insurance coverage, and unmet healthcare needs including primary care, substance use treatment, and mental health services. MSM not engaging in sex work were more likely to report access to primary and specialist care. Rates of HIV testing among these MSM were slightly lower, but they reported more STI testing, more insurance coverage, and fewer unmet needs. Preferred PrEP providers for both groups included primary care physicians, infectious disease specialists, and psychiatrists. MSWs were also willing to access PrEP in substance use treatment and ER settings.

Conclusions

PrEP outreach efforts for MSWs and other MSM should engage diverse providers in many settings, including mental health and substance use treatment, ERs, needle exchanges, correctional institutions, and HIV testing centers. Access to PrEP will require financial assistance, but can build on existing healthcare contacts for both populations.     

中华眼镜蛇咬伤致局部组织损伤三种疗法的临床疗效观察

目的对中华眼镜蛇咬伤致局部组织损伤的各种治疗方法进行疗效优劣比较,找出最佳治疗方法。方法总结我院569例中华眼镜蛇咬伤致局部组织损伤的各种治疗方法。结果治疗方法从优到劣依次是：抗蛇毒血清局部注射-糜蛋白酶局部注射-蛇伤药酒外敷-坏死组织早期切除-局部烧灼法-局部组织切开冲洗。结论中华眼镜蛇伤致局部组织损伤的治疗方法应首选抗蛇毒血清局部注射和糜蛋白酶局部注射,其次选用蛇伤药酒外敷。     

The Meeting of Waters, a possible shelter of evolutionary significant units for Amazonian fish

Identification of priority conservation areas is crucial for safeguarding freshwater ecosystems. Occurrence of unique populations and/or evolutionary significant units for key species is one of the most frequent reasons for protecting a region or location. In this study we have studied two of the most important fisheries resources of the Amazon basin, Curimata and Tambaqui, from different areas, in order to identify common zones of special diversity. Employing the Barcoding cytochrome oxidase I gene as a genetic tool, we have detected a clear differentiation of the populations inhabiting the Meeting of Waters and the rest of the basin for both species. This area corresponds to the confluence of the Solimões and the Negro rivers, of different physicochemical water characteristics, at the Brazilian city of Manaus in central Amazonas. The Meeting of Waters area (near Manaus) could be recommended as a potential area subject of special management, given its apparent role as a shelter for evolutionary significant units.     

The impact of climate suitability,urbanisation, and connectivity on the expansion of dengue in 21st century Brazil

Dengue is hyperendemic in Brazil, with outbreaks affecting all regions. Previous studies identified geographical barriers to dengue transmission in Brazil, beyond which certain areas, such as South Brazil and the Amazon rainforest, were relatively protected from outbreaks. Recent data shows these barriers are being eroded. In this study, we explore the drivers of this expansion and identify the current limits to the dengue transmission zone. We used a spatio-temporal additive model to explore the associations between dengue outbreaks and temperature suitability, urbanisation, and connectivity to the Brazilian urban network. The model was applied to a binary outbreak indicator, assuming the official threshold value of 300 cases per 100,000 residents, for Brazil’s municipalities between 2001 and 2020. We found a nonlinear relationship between higher levels of connectivity to the Brazilian urban network and the odds of an outbreak, with lower odds in metropoles compared to regional capitals. The number of months per year with suitable temperature conditions for Aedes mosquitoes was positively associated with the dengue outbreak occurrence. Temperature suitability explained most interannual and spatial variation in South Brazil, confirming this geographical barrier is influenced by lower seasonal temperatures. Municipalities that had experienced an outbreak previously had double the odds of subsequent outbreaks. We identified geographical barriers to dengue transmission in South Brazil, western Amazon, and along the northern coast of Brazil. Although a southern barrier still exists, it has shifted south, and the Amazon no longer has a clear boundary. Few areas of Brazil remain protected from dengue outbreaks. Communities living on the edge of previous barriers are particularly susceptible to future outbreaks as they lack immunity. Control strategies should target regions at risk of future outbreaks as well as those currently within the dengue transmission zone.     

Snakebites in Two Rural Districts in Lao PDR: Community-Based Surveys Disclose High Incidence of an Invisible Public Health Problem

BackgroundThe Lao PDR (Laos) is one of the least developed countries in Asia with an estimated 25% of the population living in poverty. It is the habitat of some highly venomous snakes and the majority of the population earns their living from agricultural activities. Under these circumstances the incidence of snakebites is expected to be high.MethodsTwo cross-sectional, community-based surveys were performed in Champone and Phin district, Savannakhet province, Lao PDR to estimate snakebite incidence. Multistage random sampling was used. In the first stage approximately 40% of all villages in each district were randomly selected. In the second stage 33% of all households in each village were randomly chosen. Members of the selected households were interviewed about snakebites during the previous 12 months.ResultsThirty-five of 9856 interviewees reported a snakebite in a 12 month period in Champone district and 79 of 7150 interviewees in Phin district. The estimated incidence is 355 snakebites per 100,000 persons per year and 1105 per 100,000 in Champone and Phin district respectively. All snakebite victims received treatment by traditional healers or self-treatment at home and nobody went to a hospital. Incidence of snakebites, calculated on the basis of hospital records of 14 district hospitals and Savannakhet provincial hospital, ranged from 3 to 14 cases per 100,000 persons per year between 2012 and 2014.ConclusionIncidence of snakebites is high in rural communities in Laos with significant regional differences. Poverty most likely contributes significantly to the higher number of snakebites in Phin district. Hospital statistics profoundly underestimates snakebite incidence, because the majority of snakebite victims receive only treatment by traditional healers or self-treatment in their village. There is an urgent need to train medical staff and students in management of snakebite patients and make snake antivenom available to cope effectively with this important public health problem in order to prevent fatalities and disabilities.