Failure of falciparum malaria prophylaxis by mefloquine in travelers from West Africa.

Due to the spread of chloroquine-resistant strains of Plasmodium falciparum in French speaking parts of Africa, we have found it necessary to prescribe mefloquine for antimalaria prophylaxis to travelers to this area. Weekly doses of 125 or 250 mg have been recommended for short journeys. In spite of this regimen, 16 documented cases of falciparum malaria in travelers have been recorded in the Bordeaux hospital center since October, 1988. Fifteen of these patients were tourists returning from West African countries, and one was an Ivorian student who had been on vacation to his home country. Nine of these patients were evaluated and found to have high plasma mefloquine levels. This report strongly supports the existence of mefloquine-resistant falciparum malaria in West Africa, especially in Sierra Leone, Burkina Faso, and Cote d'Ivoire.

An epidemiological study of a Schistosoma intercalatum focus in south-east Gabon.

A Schistosoma intercalatum focus in south-east Gabon was studied between July 1989 and July 1990. Among the 356 permanent residents in the village, 354 provided stool specimens and 101 (28.5%) were excreting eggs (geometric mean of egg density = 101.4 eggs/g, with a range of 1-3200). The pattern of prevalence and intensity of infection with age showed the curve usually found in schistosomiasis, i.e. increasing during the first 2 decades of life and then gradually decreasing. The analysis by stepwise logistic regression of factors shown to be important in determining infection in other schistosomiasis clearly demonstrated the significant and independent effects of both age and water contact on infection by S. intercalatum. These similarities with other schistosomal infections could indicate that similar immune mechanisms were operating. Urine from 284 subjects, of whom 90 were egg excreters, was tested for circulating antigen by enzyme-linked immunosorbent assay using a Schistosoma genus-specific monoclonal antibody (Sm 10.27.12). The test was positive for 90 subjects but only 35 of these were egg excreters. Although S. intercalatum is usually considered of low pathogenicity in man, this study showed a relationship between egg excretion and both splenomegaly and lower haemoglobin levels, even after taking into account the confounding presence of Plasmodium falciparum.

[An epidemiological study of human filariasis : loaiasis, dipetalonemiasis, tetrapetalonemiasis, in Douala fisherman of the river Wouri estuary (Cameroon) (author's transl)]. / Etude épidémiologique des filarioses humaines : loase, dipetalonémose, tétrapétalonémose, chez les pêcheurs Douala de l'estuaire du Wouri (Cameroun).

The aim of the study is to establish the prevalence of loaiasis, dipetalonemiasis, tetrapetalonemiasis, with particular emphasis on T. streptocerca infection. Eight small villages located close to Douala in the mangrove area of the Wouri estuary are visited and 788 dermic scarification prints stained with Böhmer hematoxylin are examined. Microfilariae belonging to the species L. loa are found in 11,2 p. 100 of the prints, D. perstans mirofilariae are found in 23,2 p. 100 and T. streptocerca in 6,9 p. 100. The prevalence of filariasis and the parasitic load are higher in male than in female. The older the inhabitants are, the more heavily infected they are found. Except for pruritus and craw-craw associating a filarial infection with characteristic symptoms seems to be difficult in this study.

[An epidemiological study of foci of S. mansoni bilharziosis in Minkana and Nalassi (Lekie Division, Cameroun) (author's transl)]. / Etude épidémiologique des foyers de schistosomose à S. mansoni de Minkama et Nalassi. (Département de la Lékié, Cameroun).

The epidemiological survey involved the examination of the total population of the two villages as well as the investigation of the freshwater snails in the neigbouring waters bodies. Biomphalaria camerunensis and Biomphalaria pfeifferi were found to be the intermediate hosts of Schistosoma mansoni. The cassage of eggs in the stools was more frequently observed in two groups, those aged 10-19 years and in the elderly women. The study of the prevalence of the disease by means of the indirect immunofluorescence technique on frozen sections of S. mansoni revealed that already in childhood the percentage of subjects with circulating antibodies is high. This percentage remains elevated in subsequent age groups. The geometrical mean reciprocal titers show an age and sex pattern similar to that found for prevalence. Both the percentage of positive indirect immunofluorescence tests and their respective titers were higher in patients with eggs in their stools. The immunological reaction using homologous S. mansoni antigen is more sensitive than that with heterologous S. haematobium antigen.

[Schistosomiasis due to Schistosoma intercalatum and urbanization in central Africa]. / Schistosomose due à Schistosoma intercalatum et urbanisation en Afrique centrale.

The species name of Schistosoma intercalatum, Fischer 1934 is linked to the shape and the size of his eggs, which are intermediate between those of S. haematobium and S. bovis. S. intercalatum is the instrument of an intestinal form of schistosomiasis looking like the form induced by S. mansoni but characterized by a low location of the lesions, mainly situated at the rectum and sigmoid level. The spreading area of S. intercalatum is bound to Central Africa. The foci are often urban and of a size limited to a town district. Bulinus forskalii is the intermediate host mostly involved in transmitting S. intercalatum lower Guinea strain, which is the strain found in the largest number of foci. B. crystallinus too transmits the parasite in the area of Gamba in Gabon. The Central Basin congolese strain of S. intercalatum is transmitted by Bulinus globosus. The houses where inhabitants are voiding eggs of S. intercalatum are just in front of the river bank or stream which are snails'breeding places. S. intercalatum is expending at the present time because of the development of built-up areas which are characterized by a disorganized town-planning. The disease is due to the high faecal pollution of the environment, causing a contamination of the urban hydrographic network which is the setting of schistosomiasis transmission. Although primely linked to the forest area, S. intercalatum is spreading with deforestation. Coming from the savannah area, S. haematobium is now invading the forest area, entering into competition with S. intercalatum. But since Bulinus acting as intermediate hosts of S. haematobium are more heliophilous than Bulinus transmitting S. intercalatum, urinary schistosomiasis has a tendency to supplant recto-sigmoidal schistosomiasis, especially in foci where hybridization between the two species of schistosomes is occurring.

[Imported malaria in Bordeaux in 1989. Epidemiologic, clinical and therapeutic study of 71 cases]. / Le paludisme d'importation à Bordeaux en 1989. Etude épidémiologique, clinique et thérapeutique de 71 cas.

In 1989 there were 71 cases of imported malaria admitted to the hospital in Bordeaux. This is 16.5% and 29% lower than in 1988 and 1987 respectively, thanks to the widespread use in Africa of mefloquine chemoprophylaxis. Sub-Saharan Africa is involved in 95% of cases, mainly West Africa (70% of cases), unlike the situation in 1987, and the first cases of paludism despite mefloquine chemoprophylaxis appeared during the second semester from the seasonal mid-summer recrudescence onwards, in travellers returning from this region. The most frequent species is still Plasmodium falciparum (80% of declared cases). This imported disease especially affects young adults despite regular prophylaxis in 59% of cases. It is therefore important to recommend rigorous protection against anopheles. Male predominance (sex ratio: 5.5) was greater in 1989 than in the previous two years, and French nationals represented 85% of the population. Falciparum malaria presents symptoms in 95% of cases before the end of the month following the patient's return to France, while for P. ovale the time for symptoms to appear is between 39 days and two years after return. Management of patients on their return poses a problem of information, since in 40% of cases diagnosis is made more than a week after the first symptoms. Attacks are mild in most cases (93%); among the serious cases death occurred in a 3-year-old child. Thrombopenia is the most frequent biological sign (22.5% of cases), followed to a lesser degree by anaemia and leukopenia. Mild attacks respond well to classical treatment (halofantrine, mefloquine, quinine, chloroquine), while two cases of more complicated symptoms required exchange transfusion.

[Epidemiology of certain endemic parasitic diseases in the town of Guadalupe (Republic of Sao Tome and Principe). II. Other endemic parasitic diseases]. / Epidémiologie de certaines endémies parasitaires dans la ville de Guadalupe (République de Saõ Tomé et Príncipe). II. Autres endémies parasitaires.

Stool, blood and urine specimens have been collected from 380 inhabitants of all age groups living in the small town of Guadalupe in May 1992. The seroprevalence of Falciparum malaria (96%), toxoplasmosis (73.3%), have been measured.

[Epidemiology of certain endemic parasitic diseases in the town of Guadalupe (Republic of Sao Tome and Principe) I. Schistosomiasis intercalatum and intestinal worms]. / Epidémiologie de certaines endémies parasitaires dans la ville de Guadalupe (République de Saõ Tomé et Príncipe). I. Schistosomose à S. intercalatum et verminoses intestinales.

Schistosomiasis intercalatum in known to exist in Saõ Tomé since 1988, (Corachan et al.). It is transmitted by Bulinus forskalii, (Brown et al., 1989). Stool, blood and urine specimens have been collected from 380 inhabitants of all age groups living in the small town of Guadalupe close to the Agua Traz river and Agua Polino. The prevalence of schistosomiasis by detection of S. intercalatum eggs in a 10 mg stool thick smear (Kato technique) is 25.5%. An excreted Schistosoma polysaccharide antigen, detected by means of a monoclonal antibody (Ripert et al., 1992), is found in 49.1% of the urine samples. Patients voiding S. intercalatum eggs in stools have been treated with praziquantel (40 mg/kg body weight), as recommended by WHO Expert Committee on Schistosomiasis, but it might be wise to also treat persons excreting antigen in urine. The prevalence of intestinal helminthiasis, ascariasis (73.7%), trichuriasis (73.7%) and necatoriasis have been measured.

[S. mansoni intestinal schistosomiasis]. / Bilharziose intestinale à S. mansoni.

EPIDEMIOLOGICAL DATA: Caused by Schistosoma mansoni, intestinal bilharziasis is endemic in west central Africa, the Arabic peninsula, the Caribbean Islands and the Atlantic cost of South America. Young adults emit large quantities of eggs in stools. CLINICALLY: The adult stage of Schistosoma mansoni lives in the mesenteric veins draining the colon. Its eggs are deposited in the submucosal veinules then pass into the intestinal lumen. Patients eliminating eggs massively experience abdominal pain and diarrhea with stools containing blood and mucus. Hepatomegalia develops, often with splenomegalia. Signs of portal hypertension, collateral circulation and ascitis are observed in highly endemic areas. Other less typical signs of digestive disorders such as anorexia, vomiting, or nausea, have also been reported.

[Urinary schistosomiasis]. / Bilharziose urinaire.

EPIDEMIOLOGICAL DATA: The most frequently encountered human bilharziasis, urinary Schistosoma haematobium schistosomiasis, is endemic in Africa and western Asia: 51 countries are concerned. Humans are infected by contact with water harboring snails of the genus Bulinus that emit furcocercous cercariae. Older children eliminate large quantities of schistosoma eggs in urine. CLINICALLY: Schistosoma haematobium lives in the adult form in the bladder plexus, emitting eggs into the urine. Hematuria and signs of upper urinary tract dilatation are the most frequent clinical manifestations. There has been no data substantiating a higher incidence of urinary tract infections or urinary stones in S. haematobium infested subjects. Schistosomiasis alone does not appear to play a major role in infertility. Inversely, clinical and pathology studies do persistently demonstrate an epidemiological association between urinary schistosomiasis and bladder cancer.

[Other forms of schistosomiasis]. / Autres bilharzioses.

SCHISTOSOMA INTERCALATUM: Endemic in central Africa, S. intercalatum is the causal agent of this intestinal bilharziasis, which is similar to Mansoni's disease but with a characteristic lower localization (rectum and sigmoid). The principal clinical signs are digestive disorders: abdominal pain, diarrhea or dysentery, straining, tenesmus, rectal bleeding. The moderately enlarged liver is smooth and hard but not painful, especially observed in adolescents. ORIENTAL BILHARZIASIS: Schistosoma japonicum (found in lakes in China, Thailand, Philippines, Indonesia) and Schistosoma mekongi (Melong valley) are the principal agents. Both lead to major liver fibrosis producing severe portal hypertension and growth retardation in children.

[Schistosomiasis: diagnosis and treatment]. / Diagnostic et traitement.

LABORATORY DIAGNOSIS: Eggs from Schistosoma haematobium can be found in large quantities in end-miction urine. Their elimination is favored by forced urination. Large quantities of S. mansoni, S. intercalatum, S. japonicum, and S. mekongi can be found on the surface of stools and in mucus and bloody fecal matter. Eggs from S. haematobium are exceptionally found in stools and may be identified in rectosigmoid biopsy samples. Immunological reactions can also be used to identify the species. THERAPY: Praziquantel, the drug of choice, is active against all schistosomal species. Oxamniquine is only active against S. mansoni and is not used outside Latin America. Molluscicidal agents have provided interesting results. Sanitary measures and education are essential therapeutic tools while waiting for a hypothetical vaccine.

[Focus of borreliosis in Gisenyi (Rwanda)]. / Etude du foyer de borreliose de Gisenyi (Rwanda).

As a result of the increase of relapsing fever cases in a rural area of West-Rwanda, a study of ticks collected in the houses has been performed. Ornithodoros moubata specimens were found in large amount. In patients, fever is the most frequent symptom. Serological tests performed in the surrounding area of patients with Borrelia in the blood are often positive, this confirming the ancient existence of the disease among inhabitants.

[Epidemiological study of onchocerciasis and malaria in Bamendjin dam area (Cameroon). Malacologic fauna and risks of schistosomian introduction (author's transl)]. / Etude épidémiologique de l'onchocercose et du paludisme dans la région du lac de retenue de Bamendjin - Cameroun. Faune malacologique locale et possibilités d'implantation des bilharzioses.

Report of survey in Bamendjin dam area indicates that 25 p. 100 of the population have a blood smear positive for malaria (P. falciparum) and 80 p. 100 have a positive indirect immunofluorescent test for malaria. The vector is A. funestus. In male inhabitants 23,2 p. 100 of the snip-biopsies are positive for O. volvulus and 40 p. 100 of the indirect immunofluorescent test are positive. In female inhabitants the respective ratios are 14,4 p. 100 and 48,8 p. 100. There is no urinary or intestinal schistosomiasis in this area but specimens of potential vectors have been detected.

[Sensitivity of S. intercalatum to praziquantel (author's transl)]. / Etude de la sensibilité de S. intercalatum au traitement par le praziquantel.

The stools of 35 patients with S. intercalatum bilharziasis are examined 48 hours, 45 days and 6 months after treatment, using praziquantel, a new trematodicide drug, in an individual single dose of 40 mg/kg body weight. The number of eggs per gram of faeces is not significantly reduced 2 days after treatment. After 45 days however eggs are only to be found in the stool of one patient among the 25 treated persons who were seen for control. Six months later 23 persons were examined again and 3 stools specimens were found positive, this being possibly due to reinfection. The drug has been well tolerated, except for minor side effects such as headache, nausea and abdominal discomfort.

[Imported malaria at hospitals in Bordeaux (France) in 1987 and 1988. Report of 185 cases]. / Le paludisme d'importation dans les hôpitaux de Bordeaux en 1987-1988. Etude de 185 cas.

100 cases of imported malaria were registered in Hospitals of Bordeaux in 1987 and 85 in 1988. Origin of infestation is Africa in 88 p.c. of the cases mainly from Central Africa (50 p.c.) in 1987 and western Africa (67 p.c.) in 1988. The most frequent species was Plasmodium falciparum 73 p.c. in 1987 and 82 p.c. in 1988. Admitted cases in Bordeaux were mainly French (81 p.c.) with a significant male prevailing and young adults. Mean age was 29 for Europeans and 19 for the others mainly Africans. Infestation risk is in close correlation with the duration of stay in endémic zones. It is maximum for stays between 2 and 11 months. Delay for first symptoms to appear following return from an endemic zone depends of species concerned during the first month, 83 p.c. of malaria fever at Plasmodium falciparum during the second quarter, 50 p.c. of fever at Plasmodium vivax, and after one year or more 40 p.c. at Plasmodium ovale. Only 1/4 of the cases were diagnosed during the first 48 hours. Delay in diagnosing may be prolonged and is in relationship with Plasmodium falciparum chemoresistance and self-medication. 21 strains of Plasmodium falciparum were chloroquinoresistant in vitro: 1 from French Guyana, 9 from Western Africa, and 11 from Central Africa. The strain from Guyana was also less sensible to quinine with a IC 50 = 480 nmol/l.

[Epidemiology of dracunculosis in the Mandara Mountains (North Cameroon). Organization of a control campaign]. / Epidémiologie de la dracunculose dans les Monts Mandara (Nord-Cameroun). Organisation d'une campagne de lutte.

The map of the Mandara Mountains dracuntiasis focus showing the wells and water bodies, which are the transmission sites of the disease in the study area, shows that the focus is relatively well limited. The drilling of new wells, the protection of existing water bodies used for human consumption, the health education project and the treatment of water by temephos lead to ascertain that the number of Guinea worm cases seen is decreasing every year in the area where the project is meticulously performed. These encouraging results show that it is now possible to eliminate the Guinea worm from North Cameroon by extending the operations in progress to the comprehensive surface of the focus, including the remote areas in mountains and the satellite foci in the plain along the Nigerian border.

[Hepatic distomatosis caused by Clonorchis/Opisthorchis spp. in refugees from South-East Asia. Effects of treatment with praziquantel]. / Etude des distomatoses hépatiques à Clonorchis/Opistorchis spp. chez des réfugiés d'Asie du Sud-Est. Effets du traitement par le praziquantel.

The prevalence of liver infection (percentage of patients voiding Clonorchis or Opistorchis spp. eggs in faeces) is 18.5% in the South East Asian refugees. Both sexes are equally affected and the older the refugees are, the more often they are found infected. Laotians, who like to eat the fishes raw, are harboring leverflukes more often than other Far-east inhabitants. Praziquantel, prescribed at a dose of 25 mg/kg body weight given 3 times on a single day, is very efficient in the treatment of the Far-east hepatic distomatosis. Tolerability to praziquantel is excellent. Side effects are few and of moderate intensity.

[Epidemiological study of bancroftian filariasis in the Logone Valley (North Cameroon) (author's transl)]. / Etude epidémiologique de la bancroftose dans la Vallee du Logone (Nord Cameroun).

In the Logone Valley, Yagoua and the surrounding area, the prevalence of the bancroftian filariasis was measured by means of determinating the microfilarian rate: 22,1 p. 100 in males and 9,8 p. 100 in females. The immunofluorescence test on D viteae frozen sections showed the presence of antibodies in 61,5 p. 100 of the males and 68,2 p. 100 of the females. A balance between the microfilarial rate and the percentage of inhabitants with specific antibodies was observed. Parasitological and immunological examinations appeared to be complementary. The microfilarial density is 19 microfilariae/20 microliter of blood in males and 13 microfilarae/20 microliter in females. Elephantoid extremities of scrota was observed in 13,2 p. 100 of the adult males, all of them having more than 40 years of age. Females are less affected than males. At the beginning of the rainy season, females of A. gambiae were the mosquitos the most frequently caught in the houses.