Prevalence of Chagas disease in pregnant women and incidence of congenital transmission in Santa Cruz de la Sierra, Bolivia.

Congenital transmission of Chagas disease stand out as a major public health problem since the vector control was performed in all endemic areas and has shown its effectiveness. An epidemiological study was performed in three maternity hospitals of the city of Santa Cruz de la Sierra, Bolivia from 2006 to 2008. The serological screening for Trypanosoma cruzi infection was carried out in 15,767 pregnant women. Chagas infection was detected in 3725 women (23.6%), who gave birth to 125 newborns infected by T. cruzi at birth, representing an incidence of 790 per 100,000 births during a period of 16 months and a vertical transmission rate by 3.4%. There was a significant difference between hospitals that might be explained by socio-economic origins of mothers and diagnostic constraints.

Dangerous scorpion fauna of Mali

Although the main Malian scorpion species of medical interest, Androctonus amoreuxi, is responsible for severe envenomings and perhaps some deaths, it has hitherto been considered not dangerous for humans. This population is located in the Saharian North-Eastern regions of Mali where it is accompanied by Leiurus quinquestriatus, a well known dangerous species of the Sahara. In the Gao district, divided by the Niger River, less desolate than the Tessalit and Kidal regions, one specimen of the dangerous species Androctonus australis was found. To summarize, Mali harbors at least three dangerous scorpion species: Leiurus quinquestriatus, Androctonus amoreuxi and A. australis, the latter recently having been identified in Mali for the first time. The absence of Androctonus aeneas is surprising in this context because it is found in neighboring countries (Algeria, Niger) and should be detected by new surveys. The possibility of preparing a single scorpion antivenom intended for Saharian and sub-Saharian populations is discussed.(AU)

Incidence and severity of scorpion stings in Algeria

Scorpion stings are a public health problem in the Maghreb region. In Algeria, epidemiological data were collected over the past twenty years by the Algerian health authorities. This study is an analysis of morbidity and mortality data collected from 2001 to 2010. Annual incidence and mortality due to scorpion envenoming were 152 ± 3.6 stings and 0.236 ± 0.041 deaths per 100,000 people (95% CI), respectively. The risk of being stung by a scorpion was dramatically higher in southern areas and central highlands due to environmental conditions. Incidence of envenoming was especially higher in the adult population, and among young males. In contrast, mortality was significantly higher among children under 15 years, particularly ages 1-4. Upper limbs were more often affected than lower limbs. Most stings occurred at night, indoors and during the summer. Data collected since 2001 showed a reduction of mortality by nearly 50%, suggesting that the medical care defined by the national anti-scorpion project is bearing fruit.(AU)

Snakebite on the hand: lessons from two clinical cases illustrating difficulties of surgical indication

Snakebite is a particularly important health problem in rural areas of tropical regions. A large number of victims survive with permanent physical sequelae due to local tissue necrosis. However, necrosis may be associated with compartment syndrome especially when the bite is on the hands or feet. Herein, we describe two cases reported at a rural district hospital in Central African Republic. The present study suggests that active multidisciplinary management may improve patient prognosis while evidencing how difficult it is to decide on surgical intervention.(AU)

Snakebite on the hand: lessons from two clinical cases illustrating difficulties of surgical indication

Snakebite is a particularly important health problem in rural areas of tropical regions. A large number of victims survive with permanent physical sequelae due to local tissue necrosis. However, necrosis may be associated with compartment syndrome especially when the bite is on the hands or feet. Herein, we describe two cases reported at a rural district hospital in Central African Republic. The present study suggests that active multidisciplinary management may improve patient prognosis while evidencing how difficult it is to decide on surgical intervention.(AU)

Incidence and severity of scorpion stings in Algeria

Scorpion stings are a public health problem in the Maghreb region. In Algeria, epidemiological data were collected over the past twenty years by the Algerian health authorities. This study is an analysis of morbidity and mortality data collected from 2001 to 2010. Annual incidence and mortality due to scorpion envenoming were 152 ± 3.6 stings and 0.236 ± 0.041 deaths per 100,000 people (95% CI), respectively. The risk of being stung by a scorpion was dramatically higher in southern areas and central highlands due to environmental conditions. Incidence of envenoming was especially higher in the adult population, and among young males. In contrast, mortality was significantly higher among children under 15 years, particularly ages 1-4. Upper limbs were more often affected than lower limbs. Most stings occurred at night, indoors and during the summer. Data collected since 2001 showed a reduction of mortality by nearly 50%, suggesting that the medical care defined by the national anti-scorpion project is bearing fruit.(AU)

Dangerous scorpion fauna of Mali

Although the main Malian scorpion species of medical interest, Androctonus amoreuxi, is responsible for severe envenomings and perhaps some deaths, it has hitherto been considered not dangerous for humans. This population is located in the Saharian North-Eastern regions of Mali where it is accompanied by Leiurus quinquestriatus, a well known dangerous species of the Sahara. In the Gao district, divided by the Niger River, less desolate than the Tessalit and Kidal regions, one specimen of the dangerous species Androctonus australis was found. To summarize, Mali harbors at least three dangerous scorpion species: Leiurus quinquestriatus, Androctonus amoreuxi and A. australis, the latter recently having been identified in Mali for the first time. The absence of Androctonus aeneas is surprising in this context because it is found in neighboring countries (Algeria, Niger) and should be detected by new surveys. The possibility of preparing a single scorpion antivenom intended for Saharian and sub-Saharian populations is discussed.(AU)

African Society of Toxinology: a new opportunity for integrating the control of envenomations in Africa

In Africa, snakebites and scorpion stings have long been oppressive for indigenous peoples, frightening for foreign travelers and confusing for medical personnel... In many tropical countries, studies were performed to assess the importance and management of envenomations. Since the 18th century, many works have addressed Indian venomous snakes and treatment of their bites (1, 2). In Brazil, studies began in the late 19th century (3). In Africa, apart from some systematic zoological studies in the early or mid 20th century, sustained research commenced mainly after the end of the colonial era (4-8). However to date, the incidence and mortality in Africa remain poorly known, limiting the organization of management and prediction of therapeutic needs (9). The development of research on venomous animals, venoms and envenomation truly started in North Africa in the 1960s, followed in sub-Saharan Africa in the early 1970s. The number of published studies increased significantly over the past decade, particularly with regard to sub-Saharan Africa. Considering the publications indexed in major bibliographic databases either printed (Bulletin de l'Institut Pasteur since 1903, Tropical Diseases Bulletin since 1912, Bulletin Signalétique du CNRS since 1940) or online (Pascal since 1971, Medline since 1972), the number of publications, excluding books, increased almost fivefold compared to the 1970s showing the emergence of the first African teams involved in research toxinology (Figure 1). However, publishing articles is highly dependent on congresses which are opportunities to present works completed by researchers and explain why the level of publications is so irregular from one year to the next... In addition, it should be emphasized that the clinical and epidemiological studies represent more than two thirds of published works.(AU)

[Screening for congenital infection by Trypanosoma cruzi in France]. / Le dépistage de l'infection congénitale par Trypanosoma cruzi en France métropolitaine.

The importance of congenital transmission of Chagas' disease increases with its emergence in communities infected with Trypanosoma cruzi, but where vector transmission has never existed or is fully controlled through vector control campaigns. In both endemic and non-endemic areas, the rates of mother-to-child transmission (MTCT) could be the same, by 5%, generating a constant source of new cases of the disease. Risk factors for vertical transmission are not fully elucidated, but the effectiveness of the adaptive immune response and the genetic susceptibility of both the mother and the child are suspected. Besides the risk of miscarriage or premature birth, neonatal infection by T. cruzi causes an acute form of Chagas disease, which may be accompanied by a severe infectious syndrome that can causes death if not treated early. This form of the disease is a real public health priority because it is frequent, severe, identifiable and curable. Indeed, almost all newborns diagnosed and treated before the end of their first year of life will be definitely cured. In all non-endemic areas, detection of cases of congenital Chagas disease is hampered by a very low prevalence of the disease in the general population of pregnant women, the lack of symptoms in most infected women and the disregard of these problems from health personnel in charge of monitoring pregnancy. Secondary prevention firstly consists in identifying infected women (with history of exposure and positive serology for Chagas disease) and secondly to look for the parasite in newborns from infected mothers. No primary prevention is indeed possible during pregnancy, since the only two drugs are toxic and possibly teratogenic. However, after birth, treatment could be offered to all infected women in order to prevent late complications of the disease and to make an attempt at breaking the chain of MTCT in future pregnancies.

[Study on the venoms of the principal venomous snakes from French Guiana and the neutralization]. / Etude des venins des principaux serpents venimeux de Guyane française et de leur neutralisation.

We studied some biochemical, toxic and immunological characteristics of the venoms of Bothrops atrox, Bothrops brazili and Lachesis muta, Viperidae responsible for most of the bites of venomous snakes in French Guiana. Chromatographic (HPLC) and electrophoretical profiles (SDS-PAGE), lethal, hemorrhagic, defibrinogenating, coagulant, thrombin like, proteolytic, fibrino(geno)lytic and phospholipase activities were studied. In addition, the neutralization of some toxic activities conferred by four antivenins was compared. The chromatographic and electrophoretic profiles were different for the three venoms, showing differences between Bothrops and L. muta venoms. In general, bothropic venoms showed the highest toxic and enzymatic activities, while the venom of L. muta showed the lowest lethal, hemorrhagic and coagulant activities. The enzymes of bothropic venoms responsible for gelatinolytic activity were around 50-90 kDa. All the venoms were able to hydrolyze a and beta chains of the fibrinogen, showing different patterns of degradation. Although all the antivenoms tested were effective to various degrees in neutralizing the venom of B. brazili and B. atrox, neutralization of L. muta venom was significantly better achieved using the antivenom including this venom in its immunogenic mixture. For the neutralization of L. muta venom, homologous or polyvalent antivenoms that include the "bushmaster" venom in their immunogenic mixture should be preferred.

[Envenomation and poisoning by venomous or poisonous animals. VII: arachnidism in the New World]. / Envenimations et empoisonnements par les animaux venimeux ou vénéneux. VII: l'arachnidisme du Nouveau Monde.

The incidence of scorpion stings and spider bites is high in Latin America. This is particularly true for Mexico, part of Amazonia, and southern and eastern Brazil. Centruroides and Tityus scorpion stings present a real danger for humans, especially children. Envenomation results in intense pain, neurological signs, and cardiorespiratory manifestations that can lead to death by acute pulmonary edema or heart failure. In the event of confirmed envenomation, antivenin must be administered as soon as possible in association with symptomatic treatment and, if necessary, cardiorespiratory resuscitation. Spider bites are a less frequent and severe. Envenomation by Loxosceles is extremely painful and necrotizing. Severe visceral complications can develop. An effective antivenim has recently become available for local and systemic envenomation. Envenomation by Latrodectus leads to neurological symptoms that can also be treated with antivenom. Envenomation by other spiders is less frequent and generally harmless.

[Defining an ethics for preventive trials]. / Quelle éthique pour les essais de prévention?

Preventive trials (to prevent from infection) or prophylaxis trials (to avoid consequences of the disease) differ from other clinical trials as they apply to healthy subjects or subjects considering themselves as such: the latter do not ask for intervention even less for trial. Moreover, it is generally an experiment which aims at validating a public health intervention, the individual character of which could appear as secondary regarding the collective interest. It concerns many tools or methods: preventive or prophylactic vaccines and drugs, condoms, impregnated bed nets, etc. The field of implementation of preventive trials is large and covers routine immunization (EPI), large-scale control or eradication of endemic diseases or epidemics, for which the concept of individual risk is generally better understood. Preventive trials imply ethical obligations (high individual or collective benefits and absence of risks as there is no immediate therapeutic compensation), methodological adaptations (because the number of subjects is considerably larger than for therapeutic trials) and a sensitive valorization towards a large population who is not asking for the recommended intervention. As regard the benefits, it is also necessary to consider the costs in comparison with the expected efficacy The methodological constraints are important because the demonstration of both safety and efficacy requires a very large number of subjects to validate the product. It is often necessary to use indirect or substitutive markers and indicators (title of protective antibodies rather than definite clinical protection) which need a preliminary validation. Before carrying out a preventive or prophylactic trial, it is advisable to specify the objectives in order to assess the real profits and absence of risks during the trial and after the implementation of the tested product. Preventive trials require a phase of technological transfer to guarantee the application of the validated tools for the benefit of the population at stake. In this respect, if trials for prevention are now well codified both on ethical and methodological aspects, trials for prophylaxis (filariasis with ivermectin, schistosomiasis with praziquantel, malaria with intermittent "preventive" treatment or HIV with antiretroviral treatment, for example) still remain a difficult issue at both ethical and methodological levels.

Epidemiology of scorpionism: a global appraisal.

The scorpionism is an actual public health problem in several parts of the world because, either incidence, or severity of envenomations is high and managed with difficulty by health services, or for these two reasons at the same time. The treatment of scorpion envenomation is complex and controversial, in particular regarding the utility of the antivenoms and symptomatic treatments that must be associated. The authors reviewed the literature of last 30 years to discuss the epidemiologic importance of scorpionism and to point out the principal therapeutic or preventive measures. According to the most recent studies, seven areas were identified as at risk: north-Saharan Africa, Sahelian Africa, South Africa, Near and Middle-East, South India, Mexico and South Latin America, east of the Andes. These involve 2.3 billion at risk population. The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%). Although adults are more often concerned, children experience more severe envenomations and among them, mortality is higher. Improvement of therapeutic management would reduce the lethality very significantly.

Congenital Chagas disease: diagnostic and clinical aspects in an area without vectorial transmission, Bermejo, Bolivia.

The authors carried out a 1-year study of a population of pregnant women delivering at Bermejo hospital, South Bolivia. In this area, vectorial transmission of Trypanosoma cruzi is negligible and women infect themselves during displacements in close endemic areas. The prevalence of T. cruzi in 508 pregnant women, diagnosed by several serological tests, was 33.9%. In eight infants, we observed T. cruzi in the umbilical cord (congenital transmission rate of 5.2%). The means of birth weights, lengths and hemoglobin rates were similar in the children from both seronegative and seropositive women, and in children infected or not by T. cruzi. This study could confirm a less severity of the congenital disease of Chagas in the absence of re-infestation of the mother during pregnancy. Serological screening of pregnant women by rapid diagnostic tests and examination of babies born from seropositive mothers by microhematocrit method at birth is a suitable strategy to detect and prevent congenital Chagas disease in non-endemic areas.

[Report of the 3rd International Conference on Envenomations in Africa]. / Troisième Conférence internationale sur les envenimations en Afrique. Brazzaville, 15-17 novembre 2007.

The 3rd International Conference on Envenomations was held in Brazzaville from 15 to 17 November; 2007. At this meeting, updating of epidemiological and treatment information on envenomations in Africa were presented. A round table concluded the conference drawing contributors' main recommendations. One of these recommendation pointed out the need to treat the problem of envenimations at a regional level by creating a group of experts in charge of considering the priorities as well as identifying relevant strategies of management, ensuring the plea and finding the financing.

Risk factors and consequences of congenital Chagas disease in Yacuiba, south Bolivia.

OBJECTIVE: To determine the risk factors of congenital Chagas disease and the consequences of the disease in newborns. METHODS: Study of 2712 pregnant women and 2742 newborns in Yacuiba, south Bolivia. Chagas infection was determined serologically in mothers and parasitologically in newborns. Consequences of congenital Chagas disease were assessed clinically. RESULTS: The prevalence of Chagas disease in pregnant women was 42.2%. Congenital transmission was estimated at 6% of infected mothers leading to an incidence rate of 2.6% among newborns. Main risk factors of congenital transmission were mothers' seropositivity and maternal Trypanosoma cruzi parasitaemia. Parity was higher in infected than in non-infected mothers, but it was not associated with the risk of congenital transmission. The rate of congenital infection was significantly higher in newborns from multiple pregnancies than in singletons. However, we did not observe statistically significant consequences of Chagas disease in newborns from single pregnancies or among twins. CONCLUSIONS: The main risk factors for congenital transmission were infection and parasitaemia of mothers. Consequences of the disease seemed mild in newborns from single pregnancies and perhaps more important in multiple births.

Clinical trial of an F(ab')2 polyvalent equine antivenom for African snake bites in Benin.

We report the results of a trial designed to measure the safety and efficacy of African Antivipmyn, a new freeze-dried polyvalent equine F(ab')(2)-based antivenom. We tested 289 envenomations. After treatment, 19% of treated patients had undesirable events, all benign. A possible adverse effect was attributed to this antivenom in 11% of the patients. Bleeding was observed in 48% of the patients; it stopped within 2 hours after treatment with antivenom in 60% of the patients. Blood incoagulability was observed in 80% of the patients. Restoration of coagulation was attained within 4 hours in 60% of the patients. Nine patients died; 6 arrived at the hospital in the final stage of complications and 5 arrived at the hospital more than 60 hours after the bite. The value of blood coagulation tests in diagnosis of envenomation and bleeding as an indicator of renewal of treatment are emphasized.