Trichinella pseudospiralis outbreak in France.

Four persons became ill with trichinellosis after eating meat from a wild boar hunted in Camargue, France. Nonencapsulated larvae of Trichinella pseudospiralis were detected in meat and muscle biopsy specimens. The diagnoses were confirmed by molecular typing. Surveillance for the emerging T. pseudospiralis should be expanded.

Control of Leishmania infantum infection is associated with CD8(+) and gamma interferon- and interleukin-5-producing CD4(+) antigen-specific T cells.

Visceral leishmaniasis is a severe and lethal disease caused by the protozoan parasites of the genus Leishmania. In areas where leishmaniasis is endemic, most infected individuals control the infection and remain asymptomatic; chemotherapy of visceral leishmaniasis restores some immunity which protects against relapses. In the present study, Leishmania-specific T-cell clones were established from six asymptomatic and five cured patients. Cytokines production by these clones was analyzed. A large fraction of the parasite-specific T-cell clones from asymptomatic patients were CD8(+) and produced high amounts of gamma interferon (IFN-gamma). Most CD4(+) T-cell clones from two asymptomatic subjects exhibited an unusual phenotype: production of high levels of IFN-gamma low levels of interleukin-4, (IL-4), but high levels of IL-5. In contrast, only few parasite-specific CD8(+) T-cell clones were obtained from cured patients after chemotherapy; moreover, CD4(+) T-cell clones from these patients exhibited an heterogeneous profile of cytokines from Th1-like to Th2-like phenotypes. These results point to CD8(+) T cells and to IL-5- and IFN-gamma-producing CD4(+) T cells as possible contributors to human resistance to Leishmania infection. They should stimulate new immunological approaches in the control of this disease.

[Chloroquine sensitivity of Plasmodium falciparum at the Gamkalley Clinic and the Nigerian armed forces PMI (Niamey, Niger)]. / Chloroquinosensibilité de Plasmodium falciparum à la clinique Gamkalley et à la PMI des Forces armées nigériennes (Niamey, Niger).

In vivo tests for Plasmodium falciparum were carried out in 1998 during the rainy season among children in Niamey, in the Republic of Niger. Chloroquine was prescribed at 25 mg/kg for 3 days in febrile patients with uncomplicated P. falciparum malaria. Forty-five 1-5 year-olds and thirty-three 6-15 year-olds were included in the study. A group of 53 adult patients was also surveyed to evaluate the efficacy of chloroquine in semi-immune persons. Body temperature and blood smears including parasitemia were recorded on days 0, 3, 7 and 14. Less than 10% of the patients were delinquent. Around 75% of the patients were successfully treated in the 1-5 year-olds and 6-15 year old age groups. Relapses were observed in 20% of the 1-5 year-olds (early relapses 8.9%, late relapses 11.1%) and in 16.7% in the 1-15 year-olds (early relapses 6.4%, late relapses 10.3%). Among adults, successful treatment was obtained in 86.8% of the cases and early and late relapses were respectively observed in 3.8% and 1.9% of the cases. All the patients with malaria relapses were cured with second-line treatments (pyrimethamine-sulfadoxine or quinine). According to these results, chloroquine resistance appears to be moderate in Niamey. Therefore chloroquine should remain the first line treatment of uncomplicated P. falciparum malaria in this population.

Outbreak of epidemic typhus associated with trench fever in Burundi.

BACKGROUND: After a 12-year absence, epidemic typhus has re-emerged among the displaced population of Burundi. Following the outbreak of civil war in 1993, over 760000 people now inhabit refugee camps, under appalling conditions. A typhus outbreak occurred among prisoners in a jail in N'Gozi in 1995. At the time, the disease was not recognised, and was referred to as sutama. Reports of sutama among the civilian population date back to late 1995 and, in association with body-louse infestation, the disease has subsequently swept across the higher and colder regions of the country. METHODS: During a field study in February, 1997, 102 refugees with sutama underwent clinical examination and interview. Serum samples were collected and infesting body lice removed. Microbiological analysis included antibody estimations and specific PCRs aimed at diagnosis of Rickettsia prowezekii, Bartonella quintana, and Borrelia recurrentis. Between January and September, 1997, nationwide epidemiological data on the prevalence and distribution of sutama was obtained through liaison with local health services. A second field study in March, 1997, entailed the collection of further serum samples from suspected cases of sutama in different regions of Burundi. FINDINGS: Most of the 102 patients with sutama during initial assessment presented with manifestations similar to those previously described for typhus in Africa, though skin eruptions occurred in only 25 (25%) cases. Microbiological testing revealed evidence of R prowazeki infection in 76 (75%) patients, confirming that most cases of clinically-diagnosed sutama were epidemic typhus, and supporting the reliability of clinical diagnosis as a basis for the nationwide surveillance of the disease. Up to September, 1997, 45558 typhus cases were clinically diagnosed, most of which occurred in regions at an altitude of over 1500 m. Serological testing of 232 individuals from different regions of Burundi provided microbiological evidence to support clinical diagnoses in seven provinces, confirming the widespread nature of the outbreak. Serum from 13 of the original 102 patients and 19 (8%) of the 232 suspected cases had raised antibody titres against B quintana. A fatality rate of 15% among jail inmates fell to 0.5% after administration of a single dose of 200 mg doxycycline to suspected cases. INTERPRETATION: A gigantic outbreak of R prowazekii-induced typhus and B quintana-induced trench fever is continuing in Burundi. Transmission of both diseases to such a large number of people has followed a widespread epidemic of body-louse infestation. Diagnosis of typhus could be reliably made by means of clinical criteria, and the disease could be efficiently and easily treated by antibiotics. This epidemic highlights the appalling conditions in central-African refugee camps and the failure of public-health programmes to serve their inhabitants. Louse-associated disease remains a major health threat in this and other war-torn regions of the world.

In vitro and in vivo resistance of Leishmania infantum to meglumine antimoniate: a study of 37 strains collected from patients with visceral leishmaniasis.

Primary and secondary unresponsiveness to meglumine has long been described in human visceral leishmaniasis. However, no studies have been performed to elucidate if these therapeutic failures were due to strain variability in meglumine sensitivity or were related to host factors. We have studied the in vitro sensitivity of 37 strains of Leishmania infantum isolated from 23 patients (11 human immunodeficiency virus-infected and 12 immunocompetent patients) with visceral leishmaniasis. Sensitivity tests were performed by infecting murine macrophages with Leishmania parasites and culturing them in medium containing different concentrations of meglumine. For each test we calculated a 50% effective dose (ED50) corresponding to the meglumine concentration at which 50% of the Leishmania parasites survived. In vitro results were strongly correlated to immediate clinical outcome. All strains requiring an ED50 of >70 microg/ml were related to therapeutic failures, whereas all strains requiring an ED50 of <40 microg/ml corresponded to an initial efficiency of meglumine. Among those patients who were initially improved, relapses occurred in all immunocompromised patients and in most immunocompetent patients who had a short duration of treatment (15 days). Finally, we found that in vitro sensitivity of strains decreased progressively in relapsing patients treated with meglumine. Consequently, the physician may be encouraged to alternate meglumine with other treatments such as amphotericin B or pentamidine, especially in the case of relapsing patients.

Prevalence of antibodies to Coxiella burnetti, Rickettsia conorii, and Rickettsia typhi in seven African countries.

The prevalences of antibodies reactive with Coxiella burnetti, Rickettsia conorii, and Rickettsia typhi were determined by indirect fluorescent antibody testing of sera from seven African countries. The seroprevalences of antibodies reactive with C. burnetti and R. conorii in countries from North Africa were similar to those reported from southern Europe. In countries of sub-Saharan Africa, the seroprevalence of antibodies reactive with C. burnetti varied greatly; the generally higher figures for West Africa, where stock breeding is prominent, suggested that domestic animals might be the main reservoirs of infection. The prevalence of antibodies to the recently described species Rickettsia africae was higher than that reported for spotted fever-group rickettsiae from elsewhere in the world and paralleled the distribution of Amblyomma species. Western blot results suggested that the antibodies detected were more likely to be reactive with R. africae than with R. conorii, the main vector of which (Rhipicephalus species) rarely feeds on humans. The seroprevalences of antibodies reactive with R. typhi were higher in coastal regions, where Rattus norvegicus--the natural host of the vector Xenopsylla--is more prevalent, than in inland areas.

[Apropos of 2 cases of severe malaria contracted in the port of Marseille]. / A propos de deux cas de paludisme grave contractés sur le port de Marseille.

Acute Plasmodium falciparum malaria occurred during summer 1993 in two inhabitants living close to Marseille harbour. History of blood transfusion and travel outside France were excluded as was also discarded airport malaria. Entomological investigations confirmed the absence of Anopheles breeding sites in the port area. An hypothesis is a vectorial transmission following introduction of one or several anopheles arrived on a ship coming from tropical Africa. During this season, the weather conditions were favourable to the survival of anopheles and the completion of P. falciparum sporogonic cycle. Physicians were advised to take into consideration malaria in the differential diagnosis of fever from unknown origin in any patient working or living inside or around the harbour area regardless history of previous travel in malaria endemic region.

Serologic evidence for human ehrlichiosis in Africa.

Human ehrlichiosis is a recently recognized rickettsial disease. It is caused by Ehrlichia chaffeensis, an intraleucocytic Gram-negative, obligate intracellular bacterium, grouped within the genus Ehrlichiae. Most human cases of ehrlichiosis have been diagnosed in the USA. Two cases have been reported outside of the USA, one in Europe and one in Africa. From 1 January to 30 June 1992, 765 sera from blood donors or other asymptomatic subjects in 8 African countries, including Ivory Coast, Burkina Faso, Mali, Central African Republic, Angola, Zimbabwe, Mozambique and Commores Islands, were tested by indirect immunofluorescence for the presence of E. chaffeensis antibodies. Positive sera were confirmed by Western immunoblotting. Only two of 765 sera tested were positive. One serum obtained from Burkina Faso had an IgG titer of 1:200 and one from Mozambique had an IgG titer of 1:80. Human ehrlichiosis seems to occur infrequently in Africa, although many more sera from additional African countries need to be evaluated.

[Recurrent fever episodes in an African child: diagnostic difficulties of trypanosomiasis in France]. / Accès fébriles à répétition chez un enfant africain: difficultés diagnostiques d'une trypanosomiase en France.

A young Angolian boy who had emigrated to France at the age of 2, presented with a long history of fever. Gambian Trypanosomiasis was diagnosed with peculiar aspects: 1) evolution of adult sickness with a long hemolymphatic period (first stage) and a subacute worsening period with neurologic deficit and somnolence (second stage); 2) a possible post-transfusional contamination: the young boy, born in South Angola, a nor-highly endemic area, was transfused at the age of 10 months with the blood of a donor who was subsequently treated for Trypanosomiasis; 3) a suppurating adenopathy; 4) a predominance of IgG within the hypergammaglobulinemia while IgM are the predominant immunoglobulins in this affection; 5) a hepatic toxicity of Difluoromethylornithine.

Evidence of subjects sensitized to Leishmania infantum on the French Mediterranean coast: differences in gamma interferon production between this population and visceral leishmaniasis patients.

The Marseilles region is an endemic area for visceral mediterranean leishmaniasis, but although the number of dog cases, the parasite's main host, is very high, only a few people develop the disease. We looked for sensitized healthy subjects among 25 healthy individuals living in this area by studying their in vitro lymphoproliferative response to Leishmania infantum antigens and gamma interferon synthesis. We found that 65% of tested subjects were sensitized against L. infantum. We compared their cell mediated immunity to that of 13 active Kala-Azar patients and 13 controls from non-endemic areas. In patients, results showed a specific cellular immuno-deficiency in the lymphocyte response to L. infantum antigens and a global deficiency of gamma interferon production. Interestingly, the healthy individuals from the endemic area who responded to L. infantum antigens were found to produce high gamma interferon levels after L. infantum antigen stimulation. After healing, the cell mediated-immunity of the 3 patients we followed up was similar to that of the sensitized tested healthy subjects, but the former were still producing antibodies at the time of study.

Evaluation of health and productivity of small ruminants in Africa: the example of Senegal.

The authors describe a system of investigation introduced into Senegal in 1983; their purpose is to extend knowledge about the farming of small ruminants and the epidemiological relevance of such farming. The investigations are conducted in the traditional livestock sector by using a multidisciplinary approach. The precision and reliability of the information depend on the recording and processing of data on individual animals. The system of investigation has a modular structure organised around a central module for demographic surveys. The peripheral modules correspond to specific activities: clinical surveillance, recording changes in body state, laboratory tests and a study of animal husbandry conditions and practices. The authors distinguish four levels of analysis depending on the origin of variables under consideration: a single module (level 1), the demographic module plus the peripheral module (level 2), the demographic module plus two or more peripheral modules (level 3) and one or more modules derived from experimental modification of certain features of the husbandry system (level 4). The constraints and limitations of the procedure are discussed.

[Study of cellular immunity in patients with Mediterranean visceral leishmaniasis]. / Etude de l'immunité cellulaire chez des malades atteints de leishmaniose viscérale méditerranéenne.

Cellular immunity against Leishmania infantum antigens was studied in visceral leishmaniasis patients and healthy subjects living in a endemic area. Only the healthy subjects were TTL positive with production of gamma interferon, whereas the visceral leishmaniasis patients presented a transitory inhibition of their specific cellular response mechanisms.

[Prevention of malaria in travellers and expatriates]. / Prévention du paludisme chez le voyageur ou l'expatrié.

Since the occurrence of the chloroquino-resistance, chemoprophylaxis for all is not anymore the sound principle to malaria prophylaxis for travellers and expatriates. Protection against malaria has now to be based on comprehensive actions (chemoprophylaxis, control of infecting bites, treatment of malaria cases as soon as first symptom occur), they have to be combined, as a whole or not, according to the area, the duration and the type of tropical stay, and even sometimes according to some parameters peculiar to an individual. The development of concepts concerning the epidemiology of human malaria and the use of antimalarial drugs, either as protective or curative, lead more and more to the necessity for any traveller or expatriate to take medical advice from a specialized physician.

[Imported falciparum malaria in Marseilles hospitals in 1987. Apropos of 104 cases]. / Le paludisme d'importation à Plasmodium falciparum dans les hôpitaux de Marseille en 1987. A propos de 104 cas.

Patients were composed of 85 adults and 19 children; 70 were European, 23 Comorian; malaria was contracted by 9 patients in French Guyana, 60 in Africa, 23 in Comoro Islands; prophylaxis was correct for 45 patients (nearly all of the cases with chloroquine) when the first symptoms occurred. Every case of malaria appeared during the month following their return from an endemic area. Fever was often moderate or intermittent, altered by prophylaxis and previous treatments. Some patients had a clinical profile of "visceral evolutive malaria" and 3 a cerebral malaria. The most frequent biologic alteration was thrombopenia (40 times under 100,000/microliters). No relation between parasites density and clinical profile has been identified. The sensitivity of the strains for antimalarial drugs has been studied 35 times: 28 strains were chloroquine resistant, 3 have a decreased sensitivity for quinine. Most of the resistant strains came from Central Africa. Two patients died.

[Current clinical aspects and role of parasitic density in the manifestations of falciparum malaria]. / Aspects cliniques actuels et rôle de la densité parasitaire dans l'expression du paludisme à Plasmodium falciparum.

56 patients carriers of Plasmodium falciparum were observed throughout 1987: 47 males and 9 females of a mean age of 32. The following clinical aspects were observed: Falciparum malaria: 35 cases, malaria with a low parasitaemia (less than 1,000 HPM): 5 cases, tropical splenomegaly syndrome: 3 cases, isolated bi- or tricytopenia: 10 cases, cerebral malaria: 1 case, asymptomatic carriers: 2 cases. Statistically speaking, no significant correlation was observed between parasitaemia and the following clinical and biological symptoms: fever, splenomegaly, Hb level, platelet count. However, we noted a level of parasitaemia higher in the acute forms of malaria (Falciparum malaria and cerebral malaria) than in the non typical forms (chronic visceral malaria, haematological disorders). All asymptomatic carriers, who represent "malaria infection", presented a low parasitaemia (less than 1,000 HPM).

[Resistant falciparum malaria at the F. Houphouet-Boigny hospital in Marseilles in 1985-1986-1987]. / Paludisme à P. falciparum chimio-resistant à l'hopital F. Houphouet-Boigny à Marseille en 1985-1986-1987.

Chemoresistant P. falciparum malaria emerged in South Sahara Africa during 1978 and is now more than half of the imported malaria in F. Houphouet-Boigny Hospital in Marseilles (France), consequently the annual number of malaria cases has doubled as compared to the previous years. In our study of 47 chemoresistant malaria cases, collected in 1985-1986-1987, mostly contracted in French-speaking Africa, residents and travellers were both equally affected. Curative treatment was quinine IV for severe malaria (34%), sulfadoxine-pyrimethamine (46.8%), and mefloquine (51%).

[32 cases of recurrent localized edema on return from the Tropics]. / A propos de 32 cas d'oedèmes localisés récidivants au retour des tropiques.

Thirty-two patients have been hospitalised in Marseilles since 1979 for recurrent oedema following their return from a tropical region. In spite of strong suspicion, the diagnosis of Loa loa was confirmed only five times. One patient was diagnosed with filariasis due to Mansonella perstans. The diagnosis of loiasis was usually presumptive and there were often wide variations in the laboratory findings. Two patients were thought to have an allergic reaction to diethylcarbamazine. Another patient was felt to have an allergy to streptococcal antigen. One patient who had lived in the Extreme Orient presented with an inflammatory fasciitis. Two patients presented with neurological manifestations: one with eosinophilic meningo-encephalitis, one with a neuropathy of the median nerve. In one case, the oedema was attributed to congenital lymphoedema.

[Status of drug resistance of Plasmodium falciparum in the Central African Republic. Results of studies carried out between 1984 and 1986]. / Etat de la chimiorésistance de Plasmodium falciparum en République centrafricaine. Résultats d'enquêtes menées de 1984 à 1986.

Since August 1983, several cases of chloroquine resistant malaria have been observed in caucasian adults living in the Central African Republic (CAR) despite an antimalarial prophylaxis. Between 1984 and 1985, several studies including both in vitro and in vivo tests have been undertaken in cohorts of children to determine antimalaria drug sensitivity of P. falciparum in two towns of the CAR. In Bangui, out of 60 asymptomatic schoolchildren with asexual parasite count per mm3 of blood equal (or more than) 1,000, treated using a single intake of chloroquine at a dose of 10 mg/kg, three had asexual parasites at day 7 after drug administration. Alternatively, out of 57 other children with clinical malaria treated using a total dose of 25 mg/kg of chloroquine daily distributed within a 3 day period, only one exhibited a RII resistance. In vitro tests performed in a limited cohort of 15 school children showed a high sensitivity to chloroquine, amodiaquine, quinine and mefloquine in P. falciparum malaria. In Bouar, a group of 80 preschool children attending pediatric clinic were treated using either a single dose of 10 mg/kg of chloroquine (25 children) or 25 mg/kg of amodiaquine (21 cases) or 25 mg/kg of chloroquine (34 cases) within a three days period. Asymptomatic parasitaemia persisted or reappeared in 6 children all treated with 10 mg/kg of chloroquine. Therapeutic response to amino-4-quinolines in central african children is up to now satisfactory as compared to that observed in surrounding countries. Further surveys including other rural and urban areas are needed to appreciate the evolution of the phenomenon.