Comparative evaluation of Schistosoma mansoni, Schistosoma intercalatum, and Schistosoma haematobium alkaline phosphatase antigenicity by the alkaline phosphatase immunoassay (APIA).

To know if alkaline phosphatase (AP) from schistosomes other than Schistosoma mansoni can be used as diagnostic marker for schistosomiasis in alkaline phosphatase immunocapture assay (APIA), we comparatively tested n-butanol extracts of adult worm membranes from a Venezuelan (JL) strain of S. mansoni (Ven/AWBE/Sm); a Cameroonian (EDEN) strain of Schistosoma intercalatum (Cam/AWBE/Si) and a Yemeni strain of Schistosoma haematobium (Yem/AWBE/Sh). APIA was evaluated with sera of patients from Venezuela, Senegal, and Gabon infected with S. mansoni, from Gabon infected with S. intercalatum or S. haematobium, from Chine infected with Schistosoma japonicum and from Cambodian patients infected with Schistosoma mekongi. Results indicate that 92.5% (37/40) of Venezuela sera, 75% (15/20) of Senegal sera, 39.5% (17/43) of S. haematobium sera, and 19.2% (5/26) S. intercalatum sera were APIA-positive with the Ven/AWBE/Sm preparation. APIA with the Cam/AWBE/Si preparation showed that 53.8% of S. intercalatum-positive sera had anti-AP antibodies, and 51.2% S. haematobium-positive sera cross-immunocapturing the S. intercalatum AP. APIA performed with Yem/AWBE/Sh showed that 55.8% S. haematobium sera were positive. Only two out of nine S. japonicum sera were APIA-positive with the Ven/AWBE/Sm and Cam/AWBE/Si, and no reaction was observed with Cambodian S. mekongi-positive sera. AP activity was shown to be present in all the schistosome species/strains studied. The use of APIA as a tool to explore the APs antigenicity and the presence of Schistosoma sp. infections through the detection of anti-Schistosoma sp. AP antibodies in a host, allowed us to demonstrate the antigenicity of APs of S. mansoni, S. intercalatum, and S. haematobium.

Ultrastructure of erythrocytic stages of avian Plasmodium spp. of the sub-genus Novyella and its "globule".

A globule frequently refractory, appearing blue, pale blue, or white with Giemsa stain, is characteristic of the intraerythrocytic stages of the type species and of most of the other species included at present in the subgenus Novyella. This globule is absent from the other Plasmodium sub-genera. An ultrastructural study has been performed on schizogonic stages of Plasmodium merulae from the blood of the blackbird, Turdus merula. In section the globule contains a finely granular substance suggesting a condensed or coagulated substance. It differs distinctly from a classical food vacuole by denser contents, and show in some sections (19, 23) a peripheral opaque rim with a radial arrangement of ribosomes. Except for the presence of the globule, in other details P. merulae do not diverge from the ultrastructure common to the intraerythrocytic stages of avian Plasmodium.

Morphometric and molecular characterizations of schistosome populations in Estuaire province Gabon.

The aim of this study was to test the hypothesis of the presence of hybrids between Schistosoma guineensis and S. haematobium in the Estuaire province (Western Gabon). Egg morphometry and single-stranded conformational polymorphism (SSCP) analysis on adult worms were used in order to characterize the schistosome populations of two sites. The morphology of the eggs showed three morphotypes: S. haematobium, S. guineensis and intermediate morphotypes, but the eggs of the morphotype S. guineensis were smaller compared to the values found in the literature. Furthermore, the SSCP analysis of the adult schistosomes showed that all the patterns corresponded to that of S. haematobium and gave evidence that hybrids were absent from our samples.

The utility of a nebulised intra-tracheal rat model of invasive pulmonary aspergillosis.

Invasive pulmonary aspergillosis (IPA) is of particular concern to immunodeficient patients, whose mortality rates may exceed 80%. The development of an animal model that faithfully reproduces the pathophysiology of IPA would improve the studies on diagnostic and therapeutic modes, and the use of rats as a possible model for IPA seems to have been largely overlooked. Such a model could be established with the MicroSprayer IA-1B. Male Sprague-Dawley rats (6-8 weeks old) were rendered immunodeficient by cyclophosphamide injections and a protein-deficient diet. On day D0, they were anaesthetised by inhalation of 5% isoflurane and infected by the intra-tracheal aerosolization of 100 microl of an Aspergillus fumigatus spore suspension through a MicroSprayer IA-1B. This inoculation process was simple and rapid, with no deaths observed during or immediately after the procedure. The rats regained consciousness within 1 min. Follow-up data including those for clinical factors (weight changes, mortality rate), biological factors (Aspergillus antigens) and histological factors were consistent with previous studies. The advantages of this model include the ease of animal manipulation, the reproducibility of infection and the potential for repeated blood sampling.

In vitro activity of amphotericin B, fluconazole and voriconazole against 162 Cryptococcus neoformans isolates from Africa and Cambodia.

In order to determine the potential role that various antifungal agents might have in the management of cryptococcosis in tropical areas, the in vitro susceptibility of Cryptococcus neoformans isolates from Africa ( n=52) and Cambodia ( n=110) to three antifungal agents (amphotericin B, fluconazole and voriconazole) were compared using the E-test method. The results of this study (i) confirm the value of the E-test for testing the in vitro susceptibility of C. neoformans towards voriconazole; (ii) provide the first evidence demonstrating good activity of amphotericin B, fluconazole and voriconazole against Cambodian isolates; and (iii) show there are differences in susceptibility between African and Asian C. neoformans isolates, with Cambodian isolates appearing less susceptible to the agents tested but with amphotericin B maintaining good activity.

Identification and specificity of a 38 kDa Loa loa antigenic fraction in sera from high-microfilaraemic Gabonese patients.

Circulating antigens isolated from sera of three high-microfilaraemic ( Loa loa) Gabonese patients were fractionated by gel filtration. A major component (38 kDa) was identified after SDS-PAGE and immunoblotting using sera of amicrofilaraemic patients with high level of antimicrofilariae Loa loa antibodies. The 38 kDa fraction was not found in the sera of parasitised patients or healthy controls. We looked for the 38 kDa antigen in the various stages of the filarial life cycle and found it in extracts of Loa loa microfilariae but not in somatic extracts of Loa loa male and female adult worms. This fraction could be used as a diagnostic marker in loiasis for amicrofilaraemic patients.

Visceral leishmaniasis. Persistence of parasites in lymph nodes after clinical cure.

Visceral leishmaniasis (VL) is generally associated with severe immunodeficiency (AIDS; renal, liver, and heart transplantations; haemopoietic malignancies). More rarely it can be related to an immunotolerence status such as pregnancy. Various observations report the development of leishmaniasis several months or even years after exposure to the parasite. Relapses occur rarely in patients not known to be immunocompromised, but are common after incomplete treatment. They are frequent in patients with Leishmania/HIV co-infection. Asymptomatic phases and relapses suggest that parasite can exist in the tissues for a long time before and/or after clinical onset of the disease. The mechanisms of onset of clinical leishmaniasis following exposure and infestation are highly relevant to understanding the pathology of the disease. The survival of Leishmania parasite between infection and disease or after cure is a very important issue for clinicians and epidemiologists. We describe two cases of VL occurring in a patient with lymphoma and in a pregnant woman. In both cases, parasites remained present in the lymph nodes after clinical cure.

Parasitic diarrhea in normal and malnourished children.

Diarrhea is only one of the many manifestations of intestinal parasites. Environmental influences are inescapable, regardless of an individual's state of health: in a highly endemic region, intestinal parasitic colonization is almost the rule. The clinical expression of the parasitoses, however, is largely determined by host defenses; and when they are weakened, parasitic diarrhea is frequent and severe. Protein-energy malnutrition is by far the most important cause of immune deficiency in developing countries. Diarrhea caused by Strongyloides or Giardia is common and severe in malnourished children, while well-nourished children remain healthy carriers. These parasites require specific treatment in the malnourished; and the well-nourished should have preventive treatment when they are to receive corticosteroids or immunosuppressive agents. Diarrhea caused by Cryptosporidium spp. may be severe in malnourished or immunodeficient children, and recovery is achieved only after renutrition or treatment of the immunodeficiency.

[Antiparasitic treatments in pregnant women and in children in 2003]. / Traitements antiparasitaires chez la femme enceinte et chez l'enfant en 2003.

Like antibacterial agents, antiparasite drugs for pregnant women and children must be chosen in function of the stage of pregnancy, age of the child, and expected benefit-risk ratio. While no agent is totally safe, there are few absolute contraindications. Most zones of serious endemic parasite disease are located in developing countries where parasite, bacterial, or viral conditions combined with poor nutrition treatment make it necessary to treat disease in a complex pathogenic environment that weakens pregnant women and children with multiple parasite infections. In both temperate and tropical zones, there have been few real therapeutic advances involving release of new products on the market or development of new indications for existing products. Constant appearance and extension of hematozoa resistance to conventional and even more recent antimalarial agents have prompted research to find new active drugs and long-lasting treatment combinations. Real therapeutic breakthroughs have resulted from the need to develop safe drugs without substantial side-effects for single-dose use in control programs against endemic parasite diseases in mass populations including pregnant women and young children in tropical zones. There are several notable examples in the field of major verminous diseases. Ivermectin is a versatile drug that can be used against filariasis as well as for management of intestinal worms or ectoparasitosis in temperate and tropical countries. Praziquantel is an important advance in platyhelminthiasis, especially bilharziais. Triclabendazole, the latest addition to the benzimidazole family, has shown promise as a substitute for bithionol, that is difficult to procure and not recommended in pregnant women, for treatment distomiasis occurring in pregnant women and children. Other examples include albendazole against giardiasis, nitazoxamide against cryptosporidiosis, artemisinine against bilharziasis, and paramomycine, not recommended in pregnant women, against leishmaniasis.

Changes in schizogony and drug response in two lines of rodent Plasmodium, P. berghei NK 65 and P. berghei ANKA.

White mice were infected with two strains, ANKA and NK 65, of Plasmodium berghei. The parasites were subjected to chloroquine pressure (60 mg/kg at each passage) during 20 passages. We then compared the behaviour of the strains as they acquired chemoresistance. The drug resistance was estimated by the 2% delay time test (D2%), and the schizogonic rhythm by the synchronicity index (SI). Before drug pressure, the ANKA strain had a D2% of 4.34, and a SI of 0.2. This strain became highly drug resistant, but synchronicity increased: the D2% was 2.93, and the SI was 0.36 at the 20th passage. The NK 65 strain had an initial D2% of 4.12, and an SI of 0.2. The chemoresistance acquired during 20 passages was very irregular for this strain: after drug pressure, the D2% was 2.03 and the SI was 0.28. Drug pressure was then removed (for both strains), for 10 passages (no chloroquine). Resistance and synchronicity returned to their initial values. The two strains behaved very differently, in terms of their affinity for reticulocytes, and with chloroquine activity which favours an increase in SI because only merozoites are preserved.

[Human onchocerciasis and "sowda" in the Republic of Yemen]. / Onchocercoses humaines et "sowda" en République du Yémen.

The geophysics of the north Yemen, associating a north-south directed mountainous fish bone (rising in more of 2,000 meters), to numerous rivers or "wadis" is convenient to the development of simulium shelters, main vectors for cutaneous filariasis to Onchocerca sp. Following several missions of bio-clinical and epidemiological evaluations in neighbouring villages of wadis, it has been possible to study different clinical aspects: one reminding the classical african onchocerciasis with generalized and diffused dermatitis, and, on an other hand, a hyperreactive dermatitis on one side of the body and associated with a collateral lymphatic ganglion. This disease is well known for local populations as "aswad" meaning "black" or "sowda". Clinically whatever the studied focus, coexists the two types of onchodermatitis (uni or bilateral). Yhe sowda patients are proportionally less numerous than those touched by the generalized type. Frequent eye lesions of the West African onchocerciasis are not found in sowda cases. In classical optical microscopy, microfilaria is morphologically indifferenciable between sowda and onchocerciasis clinical aspects. Skin snips were carried out on patients of both groups. Identification of microfilaria by molecular biology through the study of the DNA genome was done out of 5 skin snips. Microfilaria was kept dry between laminas and the DNA extracted from rehydrated microfilaria. DNA was intensified with specific primers of Onchocerca type (O150PCR). This phase was followed by hybridisation of amplification products by PCR to specific stains: OVS-2 for Onchocerca volvulus species, OCH for Onchocerca ochengi, PFS1 and PSS1-BT respectively for the forest strain and the savannah strain of Onchocerca volvulus as described previously. We can distinguish 2 kinds of answers based on the clinical origin of the snip-tests: the first one concern 3 patients with numerous dermal microfilariae but without any clinical sowda and corresponding to microfilaria O. volvulus type but different from the forest or savannah strains found in sub-Saharan Africa. The second one corresponds to 2 patients with less than 5 microfilaria in their snip-test. They show the typical clinical picture of sowda. They are identified as microfilaria type Onchocerca but they do not belong to species volvulus, or to species ochengi. It seems quite probable that the clinical picture of sowda be the result of developing onchocerciasis of animal origin and not identified as to day. The ivermectin, therapeutic of choice for African onchocerciasis in annual unique cure seems less effective in the coverage of sowda. In that case rehearsal of cures every 3 months would be necessary for mass campaigns to limit the transmission of this filariasis.

Isoenzymes of human lice: pediculus humanus and P. capitis.

Human lice (Phthiraptera: Pediculidae) from Africa, America and Europe were electrophoresed for 28 enzymes, with special interest in metabolic factors likely to be involved with insecticide resistance. Zymogram profiles of the body louse (Pediculus humanus L. from France and U.S.A.) and the head louse (P. capitis DeGeer from France, Madagascar, Mali & Senegal) were compared. Only esterase two enzymes, phosphoglucomutase (Pgm) and 3 (Est-3), showed electrophoretic variation. In our starch gel electrophoresis conditions, P. humanus showed three electromorphs of Pgm migrating anodally 6, 11 and 16 mm (designated alleles a, b, c, respectively). Of the putative Pgm alleles, b and c occurred in all samples of both species of lice, whereas allele a was found only in P. humanus lab strain from U.S.A. Esterase 3 had four electromorphs migrating 23, 26, 30 and 35 mm (designated alleles a, b, c and d). Among putative Est alleles, a was found only in P. capitis from Bamako (all 14 specimens aa homozygotes), allele d was found only in P. capitis from Dakar (39% frequency), whereas Est-3 alleles b and c showed apparently balanced polymorphism in all samples of both P. humanus and P. capitis except that from Bamako. Despite the limited amount of isoenzyme variation detected (only 2/31 polymorphic loci), divergences of Est-3 and Pgm among Pediculus populations may be relevant to their biosystematics and resistance.

An analysis of the safety of the single dose, two drug regimens used in programmes to eliminate lymphatic filariasis.

This review of the safety of the co-administration regimens to be used in programmes to eliminate lymphatic filariasis (albendazole + ivermectin or albendazole + diethylcarbamazine [DEC]) is based on 17 studies conducted in Sri Lanka, India, Haiti, Ghana, Tanzania, Kenya, Ecuador, the Philippines, Gabon, Papua New Guinea, and Bangladesh. The total data set comprises 90,635 subject exposures and includes individuals of all ages and both genders. Results are presented for hospital-based studies, laboratory studies, active surveillance of microfilaria-positive and microfilaria-negative individuals, and passive monitoring in both community-based studies and mass treatment programmes of individuals treated with albendazole (n = 1538), ivermectin (9822), DEC (576), albendazole + ivermectin (7470), albendazole + DEC (69,020), or placebo (1144). The most rigorous monitoring, which includes haematological and biochemical laboratory parameters pre- and post-treatment, provides no evidence that consistent changes are induced by any treatment; the majority of abnormalities appear to be sporadic, and the addition of albendazole to either ivermectin or DEC does not increase the frequency of abnormalities. Both DEC and ivermectin show, as expected, an adverse event profile compatible with the destruction of microfilariae. The addition of albendazole to either single-drug treatment regimen does not appear to increase the frequency or intensity of events seen with these microfilaricidal drugs when used alone. Direct observations indicated that the level of adverse events, both frequency and intensity, was correlated with the level of microfilaraemia. In non microfilaraemic individuals, who form 80-90% of the 'at risk' populations to be treated in most national public health programmes to eliminate lymphatic filariasis (LF), the event profile with the compounds alone or in combination does not differ significantly from that of placebo. Data on the use of ivermectin + albendazole in areas either of double infection (onchocerciasis and LF), or of loiais (with or without concurrent LF) are still inadequate and further studies are needed. Additional data are also recommended for populations infected with Brugia malayi, since most data thus far derive from populations infected with Wuchereria bancrofti.

[Toxoplasmosis in Dakar. Seroepidemiologic sampling of 353 women of reproductive age]. / La toxoplasmose à Dakar. Sondage séroépidémiologique chez 353 femmes en âge de procréer.

Thanks to a serological survey carried out in Dakar from January to November 1993 among 353 procreative women, immune cover regarding toxoplasmosis was assessed using ELISA methodology: 40.2% of the surveyed population had antibodies of toxoplasmosis. No evidence of age, pregnancy, number of previous pregnancies was noted in antitoxoplasmosis antibodies prevalence. The seroconversion risk seems to be low even when it has existed during pregnancy. Contamination occurred during childhood. Some sanitary education should be provided to the procreative population in order to achieve a better compliance with basic hygiene regulations during pregnancy.

Specificity of the solid phase alkaline phosphatase immunocapture assay for the diagnosis of human Schistosoma mansoni infection.

The species specificity of the solid phase alkaline phosphatase immunocapture assay (APIA) for the immunological detection of human immunoglobulin G antibodies to the alkaline phosphatase of adult Schistosoma mansoni was evaluated. Sera from schistosomiasis patients from South America, West Africa, south-east Asia and uninfected control subjects were compared. Only the sera of patients infected with S. mansoni gave positive results. There was no apparent difference between 2 populations infected with S. mansoni, one from South America and the other from West Africa. The results with sera from various regions of West Africa were also indistinguishable. Although the APIA was not able to discriminate the geographical origin of the S. mansoni-infected subjects, the method appeared to be specific for S. mansoni and suitable for use in the immunodiagnosis of schistosomiasis mansoni, particularly in endemic areas where mixed infections of Schistosoma spp. occur.