[Diagnosis and monitoring of hemorrhage due to viper envenomation in the African savanna]. / Diagnostic et surveillance des hémorragies dues aux envenimations vipérines en savane africaine.

A study on blood incoagulability due to snake bites was carried out in the Soudanian savanna of North Cameroon, in a provincial hospital receiving patients with severe envenoming coming from areas within 250 km of the hospital. Clinical and biological examinations were conducted on 57 voluntary patients to determine the aetiology of blood incoagulability. The aetiology of this syndrome is complex and seems to depend on the variability of venom components and/or the time between bite and hospital admission inducing a diversity of biological signs. Furthermore, the presence of bleeding and the 30 minute whole blood clotting test performed in dry tube were tested in view to propose simple diagnosis and monitoring indicators. It appeared that the combination of the two indicators allowed an early diagnosis of blood incoagulability and a valid monitoring test particularly well adapted to peripheral African health centres. The recommended treatment is intravenous immunotherapy using F(ab')2, renewed in case of persistence of bleedings or a whole blood clotting test higher than 30 minutes. However, the interval between immunotherapy administration renewals remains to be defined.

Short report: treatment of snake envenomations by a new polyvalent antivenom composed of highly purified F(ab)2: results of a clinical trial in northern Cameroon.

A clinical trial was conducted in 2 health centers in northern Cameroon to assess the safety and efficacy of a new polyvalent antivenom composed of highly purified and pasteurized F(ab')2 (FAV-Africa). Forty-six patients with objective signs of envenomation, including 67% with hemorrhage, were included in the study. Each patient received at least 20 ml of FAV-Africa by direct, slow intravenous injection; 172 10-ml ampules were administered. All patients were clinically cured after treatment. Two patients (4.3%) showed minor immediate adverse events that may have been related to FAV-Africa (induration, light-headedness); no other treatment-related adverse event occurred. No patient had serum sickness. This trial confirms the safety of FAV-Africa administered by intravenous injection and its efficacy in the treatment of snake envenomations in sub-Saharan Africa.

[Validity of a test for diagnosis and monitoring of hemorrhagic syndrome after viper envenomation in sub-saharan Africa]. / Validité d'un test de diagnostic et de surveillance du syndrome hémorragique lors des envenimations vipérines en Afrique sub-saharienne.

The purpose of this study was to validate a test for diagnosis and monitoring of hemorrhagic syndrome following viper envenomation in sub-Saharian Africa. A total of 276 patients treated at 7 health centers or hospitals in North Cameroon were included. Hemorrhage was observed in 144 patients (52.2%). Coagulation time was longer than 30 minutes in 196 patients (71%). Overall hemorrhage and/or prolonged coagulation time was noted in 223 patients (80.8%). Combination of these two findings was a reliable indicator for diagnosis and monitoring. Observation of one of these factors, i.e. hemorrhage or prolonged coagulation time, indicates immunotherapy using F(ab')2. This treatment should be continued until the indicator disappears and renewed in case of relapse.

Clinical safety of a polyvalent F(ab')2 equine antivenom in 223 African snake envenomations: a field trial in Cameroon. VAO (Venin Afrique de l'Ouest) Investigators.

A large-scale clinical trials was conducted, according to World Health Organization Good Clinical Practice guidelines, in 7 centres in north Cameroon to determine the safety and efficacy of a polyvalent antivenom composed of purified F(ab')2. This study included 223 patients presenting clinically with obvious snake bite, predominantly due to Echis ocellatus (viper), the most abundant species in this savannah region. Clinical surveillance was maintained for 5 d in all patients and until the twenty-sixth day in 74% of cases. Two 10 mL ampoules of polyvalent F(ab')2 equine antivenom (Ipser Africa) were administered to each patient by intravenous infusion. If necessary, treatment was repeated 1 h after the end of the first infusion, and then with a frequency determined by the patient's clinical condition. Before initiation of antivenom treatment, the main clinical disorders observed on admission were oedema (93.7%) and haemorrhage (48.9%), with a clotting time longer than 30 min in 65.4% of patients. Clinical cure was obtained in 213 patients (96.8%). No amputation was necessary, and the case fatality rate was only 1.3%. On average, 4.6 (+/- 3.7) ampoules were administered per patient; 43% of subjects recovered after only a single infusion of 2 ampoules. Early adverse reactions, of varying degrees of severity, were observed in 6.3% of patients. A severe early reaction, anaphylactic shock, was observed in only one patient (0.4%). Serum sickness was observed in another patient. Polyvalent F(ab')2 equine antivenom given by repeated 20 mL intravenous infusions is a safe and effective treatment for envenomation caused by African vipers.

Serological and virological characterization of HIV-1 group O infection in Cameroon.

OBJECTIVES: To study the presence of HIV-1 group O infection among HIV-infected people in Cameroon and to further characterize the HIV-1 group O infections. DESIGN AND METHODS: During a 2-year survey (1994-1995), all samples tested positive in screening methods in the National Reference and Public Health Laboratory, Centre Pasteur, Yaoundé, Cameroon were identified as HIV-1 group M, HIV-1 group O or HIV-2 by using a serological algorithm. HIV-1 group M and HIV-1 group O were distinguished on the basis of competitive enzyme-linked immunosorbent assay (ELISA) reactivity against gp41 group M recombinant protein. HIV-1 group O infections were confirmed by using group O-specific V3 synthetic peptides. HIV-1 group O strains were isolated by lymphocyte cocultures, proviral DNA was amplified with specific primers, and sequencing was performed on the C2V3 and gag regions. RESULTS: Of the 8,331 screened samples, 3,193 were HIV-reactive, 2,376 (74%) of which were considered to belong to group M. The 817 (26%) that had reacted poorly or not at all against group M gp41 were further characterized: 10 were confirmed as HIV-2 and 82 as HIV-1 group O, the others being indeterminate (n = 285) or negative (n = 440). The frequency of group O relative to group M ranged from 1% in Far North province to 6.3% in the capital. There was no difference in sex, age or frequency of clinical manifestations between group M and group O infections. Group O infection was confirmed in a subset of cases by polymerase chain reaction (n = 14), with perfect concordance. Sequencing and phylogenetic analyses confirmed the high variability inside group O. CONCLUSIONS: Group O and group M epidemiological patterns are known to be similar so the reason for the lower prevalence of group O remains to be found. The wide distribution of group O infection in all Cameroonian provinces underlines the importance of further characterizing the epidemic spread and diffusion of this group.

A predictable comeback: the second pandemic of infections caused by Neisseria meningitidis serogroup A subgroup III in Africa, 1995.

Between 14 January and 4 April 1995 we isolated and characterized 44 meningococcal strains in Cameroon, Chad, Niger, and Burkina Faso; among these was the strain A:4:P1.9/clone III-1, which was involved in the second meningitis pandemic. This isolate was found in the clonal form in Niger and strains of the ET-37 complex were also found in the other three study countries, but apparently did not cause epidemics. One strain (Y:2a:P1.2,5 (ET-37 complex)) was isolated in January 1995 and another (A:4:P1.9) in March 1995 in Garoua (Cameroon). Eight strains were isolated in Moundou (Chad) between January and April 1995: the A:4:P1.9/clone III-1 (1 strain); members of the ET-37 complex (Y:2a:P1.2,5 (4 strains), Y:NT:P1.2,5 (1 strain), and Y:2a:-(1 strain)); and serogroup X (1 strain). In Niger, 31 strains were isolated between February and April 1995 from different regions. All were A:4:P1.9/clone III-1; between November 1994 and April 1995 there were 23814 cases of meningitis reported of which 2227 resulted in death. Three strains were isolated in Burkina Faso in April 1995: two were Y:2a:P1.2,5 (ET-37 complex) and one was A:4:P1.9/clone III-1. Thus in 1995 the epidemic and invasive strain (A:4:P1.9/clone III-1) responsible for the second pandemic was present in the four countries (Cameroon, Chad, Niger and Burkino Faso) that make up the area frequently affected by such epidemics and where cases are generally reported during the dry season.

Enquête "connaissances, attitudes, pratiques" et séroprévalence VIH1 chez les prostituées et filles "libres" de Mbaimboum (Cameroun)

Cette étude confirme que le taux de séroprévalence pour l'infection à VIH1 est préoccupant dans cette région frontalière. La situation géographique exceptionnelle de ce village; et l'importance des transactions commerciales qui y sont effectuées en font un point de convergence pour des femmes se livrant à la prostitution. S'installe alors; une prostitution occasionnelle non contrôlée qui fait de ce village un foyer épidémique important et une source potentielle de dissémination. Ce modèle n'est pas unique et montre que l'épidémie gagne les zones rurales par l'intermédiaire des places marchandes ou il devient impératif d'apporter aux populations l'information et l'éducation nécessaires. Ainsi les prostituées et les filles libres sont des populations cibles qu'il conviendrait d'informer et d'éduquer rapidement et en priorité dans ces régions si l'on ne veut pas voir la situation exploser dans un avenir proche

Enquete C.A.P.C. et de sero-prevalence VIH 1 a Mbaimboum; marche frontalier du Nord-Est du Cameroun : etude en population generale

Cette etude montre que le taux de seroprevalence pour l'infection a VIH 1 est preoccupant dans cette region frontaliere. La situation exceptionnelle de ce village a la conjonction du Tchad; de la Republique Centrafricaine et du Cameroun; sur un axe de commerce avec le Nigeria laisse a penser que l'avancee se fait le long des axes routiers par l'intermediaire de la prostitution. Ainsi les prostituees; les filles libres et les camionneurs sont des populations cibles qu'il conviendrait d'informer et d'eduquer rapidement et en priorite dans cette region si l'on ne veut pas voir la situation exploser dans un avenir proche