Accurate identification of Anopheles gambiae Giles trophic preferences by MALDI-TOF MS.

The determination of the trophic preferences of the Anopheles gambiae Giles (Diptera: Culicidae) is a decisive parameter for the monitoring and the prevention of malaria risk transmission. Currently, arthropod blood feeding sources are identified using immunological or molecular biology traditional techniques. Despite the effectiveness of these methods, they present several limitations, and notably, they are time-consuming and costly techniques. A recent study demonstrated that MALDI-TOF MS could be a useful tool for the identification of blood meal origins in freshly engorged mosquitoes. However, the limited number of blood vertebrate species tested to date, did not allow an assessment of the efficiency of MALDI-TOF MS in distinguishing blood MS spectra among close host species, such as humans versus primates. Therefore, in the present study, blood from ten distinct vertebrate host species, including four domestic species, four wild species, and two primates, was selected to control the reliability of MALDI-TOF MS based identification. Host blood species-specific MS profiles, up to 24h post-feeding in engorged Anopheles abdomens, were confirmed. Blind tests underlined the high specificity of MS spectra for the recognition of each host species, preventing misidentification. Nevertheless, an accurate analysis of the results from MS spectra queried against the MS database revealed that the reliability of identification is directly linked to the comprehensiveness of the MS reference database. Finally, the rapidity, the low-cost reagents, the simplicity of data analysis, and the accuracy of the tool for blood origin determination, make this proteomic strategy a promising complementary method for the elucidation of host/vector interactions.

Experimental Onchocerca volvulus infections in mangabey monkeys (Cercocebus atys) compared to infections in humans and chimpanzees (Pan troglodytes).

Three chimpanzees, three mangabey monkeys (Cercocebus atys), and 14 patas monkeys (Erythrocebus patas) were inoculated with L3 Onchocerca volvulus of Guatemalan origin. One chimpanzee and two mangabey monkeys developed antibody activity to at least three different antigens. Both mangabey monkeys recognized a 20 kDa antigen 3.5-5 months post-inoculation, and the monkeys and the chimpanzee developed antibody activity to 14 and 22 kDa antigens 7.5-13 months post-inoculation. One mangabey monkey and the chimpanzee became microfilaria-positive in skin snips at 16 and 21 months post-inoculation, respectively. Antibody activity to the 20 kDa antigen in the mangabey monkeys is noteworthy because of the prominence of this antigen among putatively immune persons living in onchocerciasis-endemic areas. The two mangabey monkeys responded parasitologically in a manner comparable to immune humans. No microfilariae were detected in one monkey and only scant numbers of microfilariae were observed in the second. The mangabey monkey may be a good animal model for the study of onchocerciasis.

Uptake and development of Wuchereria bancrofti in Aedes aegypti and Haitian Culex quinquefasciatus that were fed on a monkey with low-density microfilaremia.

Colonized mosquitoes of Culex quinquefasciatus (Haitian strain) and Aedes aegypti (Liverpool strain) were blood fed on a patas monkey (Erythrocebus patas) that had been experimentally infected with the Haitian strain of Wuchereria bancrofti and harbored a consistently low microfilaremia (1-3 mf per 20 mm3). Both species ingested more than twice the expected number of microfilariae (mf), i.e. 1.9 and 0.77 mf per mosquito, respectively. However, at 10-16 hours post ingestion only 4.2% of the mf had migrated from the blood meal in Cx. quinquefasciatus versus 20.7% in Ae. aegypti. Subsequently, only 3.5% of the ingested mf developed to the third stage in Cx. quinquefasciatus versus 56% in Ae. aegypti.

The immune response to nematode parasites: modulation of mast cell numbers and function during Strongyloides stercoralis infections in nonhuman primates.

Mucosal mast cell numbers are modulated in the intestines of rodents during parasitic infections. These mast cells can degranulate in response to worm antigens, and this event has been suggested to play a protective role for the host. To examine whether mast cells in higher animals play a role in protecting from disseminated parasitic disease, mast cell numbers and responsiveness to parasite antigens were evaluated in 5 Erythrocebus patas infected with the human intestinal nematode Strongyloides stercoralis. Initial infection and subsequent challenge infections were associated with increase in jejunal histamine and mast cell numbers, and these mast cells could release histamine in response to parasite antigens. Jejunal mast cell numbers returned to normal during a chronic phase of infection. The cells lost their ability to respond to antigenic stimulation following limited steroid treatment. Subsequent activation of chronic infections to fatal disseminated disease by more prolonged steroid treatment was associated with a marked decrease in jejunal mast cell numbers and histamine. In one animal which succumbed to severe disease without steroid treatment, jejunal mast cells were refractory to worm antigens.

Loa loa: development and course of patency in experimentally-infected primates.

Loa loa infections were studied in baboons, rhesus and patas monkeys. Animals were infected either by s.c. injection of third-stage larvae (L 3) or by surgical implantation of juvenile worms of known age, sex and number. Microfilaremia was first detected in baboons at 140 days following inoculation of L 3 and at 142 days and 143 days in patas and rhesus monkeys, respectively; the mean prepatent period was 151 days in baboons, 149 days in patas monkeys and 169 days in rhesus monkeys. The primary wave of microfilariae (mf) was suppressed by the spleen in all three primate species. In baboons, the initial wave of mf lasted from 11 to 46 weeks (mean: 22 weeks), whereas in patas monkeys it persisted for 47 to 60 weeks, and in rhesus monkeys for 1 to 2 years. Gross and microscopical changes in the spleen were noted in all three primate species and consisted of numerous granulomata in the red pulp underlying the capsule. A resurgence of mf was observed following splenectomy in all three species of monkeys. Postsplenectomy levels of microfilaremia typically exceeded presplenectomy levels. One pair of worms was sufficient to produce patent infections in monkeys for extended periods of time. However, levels of microfilaremia were lower than in monkeys which received 75 and 200 to 300 L 3, although some overlap in microfilaremias between groups did occur. Overall, there was no proportional relationship between levels of microfilaremia and numbers of adult worms recovered from monkeys at necropsy. It was observed that, in the primate host, Loa is a long-lived parasite. Living worms were recovered from the tissues as long as 9 years after inoculation and there was no reason to doubt that patency would have persisted for some time into the future. Adult worms were frequently observed moving freely in the subcutaneous tissues of the primate hosts, although no instance of Calabar swellings or the presence of worms in or around the eye were ever recorded. The primate model of loiasis is an especially useful system because of the predictability of the behavior of the parasite. In most regards, the behavior of L. loa in the primate host is comparable to observations on the parasi e in man.(ABSTRACT TRUNCATED AT 400 WORDS)

Experimental disseminated strongyloidiasis in Erythrocebus patas. I. Pathology.

Fatal disseminated disease was induced in ten patas monkeys infected with two Southeast Asian strains of Strongyloides stercoralis. While some animals died within 6 weeks after infection, others controlled their infections until placed on high doses of corticosteroids. Larvae were first noted in the stools 11-20 days after transcutaneous exposure to filariform larvae. Daily larval counts tended to increase as the infections progressed, but the number of larvae in the stool was not predictive of whether a monkey would control his infection or succumb to fatal disease. Hyperinfection was confirmed in the six monkeys in which counts were made of the adult female parasites in the duodenum at postmortem, as well as by pathologic findings in all animals. Clinical signs of disease were vague until dyspnea induced by terminal pulmonary hemorrhage occurred. Eosinophilia and/or basophilia were noted intermittently in some infections. Severe necrotizing duodenitis, colitis, and pulmonary hemorrhage were the most conspicuous postmortem findings. Hyperinfection has been predictably induced in a cercopithecoid monkey for the first time; a species which may lend itself to further investigations into the pathogenesis of disseminated strongyloidiasis .

Mansonella ozzardi: a redescription with comments on its taxonomic relationships.

Mansonella ozzardi is redescribed from adult worms collected from the subcutaneous tissues of patas monkeys (Erythrocebus patas) infected with a Haitian strain of the filaria. The worms are small and very slender; females measure about 49 mm in length by 0.15 mm in diameter and males, 26 by 0.07 mm. Haitian (Caribbean) and Colombian (Amazon) forms of the filaria are morphologically identical, as are their microfilariae. Mansonella is most closely related to Tetrapetalonema. Based on taxonomic priority the latter becomes a synonym of Mansonella. As a consequence, T. perstans and T. streptocerca of man in Africa are designated as M. perstans (Manson, 1891) n. comb. and M. streptocerca (Macfie and Corson, 1922) n. comb. Further, M. ozzardi is most closely related to the species M. llewellyni (Price, 1962) n. comb., a parasite of the raccoon, and M. interstitium (Price, 1962) n. comb. found in squirrels, both in North America.

Development and larval morphology of Loa loa in experimental primate hosts.

Experimental infections with Loa loa were established in laboratory primates by inoculation of third-stage larvae recovered from either Chrysops silacea infected after engorging on a human volunteer with loiasis, or Chrysops atlanticus infected after blood feeding on experimentally infected primates. The third molt occurred at 16 to 20 days postinoculation of infective larvae, and the fourth at about 50 days. Early larval development was characterized by rapid growth and marked differentiation of the reproductive systems. Differences in the body's growth rate between the sexes were seen as early as 30 days and was especially marked by 60 days. Females grew more rapidly, and for a longer time than males. Males reach maximum size by 120 days, females not until about 300 days. Female worms were inseminated prior to day 90 developing eggs filled the uteri by 120 days, and microfilariae appeared in the peripheral blood at approximately 150 days. Morphological features of the larval and adult stages of human Loa loa are described.

[Schistosoma mansoni experimental schistosomiasis in Erythrocebus patas monkeys (author's transl)]. / La schistosomiase expérimentale à Schistosoma mansoni chez le singe Erythrocebus patas.

A number of Erythrocebus patas monkeys have been experimentally infected only once, with Schistosoma mansoni local strain. The various parasitological, biological and immunological observations show that E. patas is a very adequate host to Schistosoma mansoni and that it develops an intestinal schistosomiasis parasitologically very close to human schistosomiasis. It is noted that in this case of single infection E. patas reactions are the same as the other species generally used in the experiments on S. mansoni.

Loa loa: development to the infective stage in an American deerfly, Chrysops atlanticus.

Chrysops atlanticus, an American species of deerfly collected along the Mississippi Gulf Coast, will support the development of the microfilaria of human Loa loa to the infective stage. Development takes place in the fat body of the fly and requires 9 to 10 days of development and pattern of morphogenesis of the parasite in C. atlanticus is virtually identical to that described in natural African vectors. Chrysops atlanticus will support the development of large numbers of L. loa to the infective stage without apparent ill effects. Two uninfected patas nonkeys each were given 75 third-stage larvae obtained from experimentally infected C. atlanticus. Both animals developed patent infections in approximately 5 months, clearly demonstrating that the entire life cycle of Loa loa can be maintained in the laboratory outside endemic areas.

Loa loa: experimental infection in two species of African primates.

Four species of primates, baboon (Papio anubis), patas monkeys (Erythrocebus patas), green monkey (Cercopithecus aethiops) and chimpanzee (Pan troglodytes) were inoculated with third-stage larvae of a human strain of Loa loa from Cameroon, West African. The baboon and patas monkeys developed patent infections after 135 to 148 days; the green monkeys and chimpanzee did not. In each animal which became patent, microfilaremia rose rapidly to high levels. In the baboon, but not in the patas monkeys, there was a suppression of microfilaremia during the 4th month of patency. After splenectomy, microfilariae reappeared in the peripheral blood in large numbers. In both baboon and patas monkeys, the microfilariae of Loa loa maintain the diurnal periodicity so characteristic of their behavior in man.