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S Karch

Publications and source records attributed to S Karch.

16 recordsLinked to original sources

[First report of Aedes albopictus (Skuse, 1984) in metropolitan France].

The first record of Aedes albopictus in metropolitan France has been made in a village of Orne (Basse-Normandie). A few larvae were collected in October 1999, in the used tire stock of an important tire recycling company, importing in particular from the USA and Japan. Reproduction of the species has taken place in France, and the environmental conditions make the implantation of the species probable.

Aedes↗

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Drug and Narcotic Control↗

Malaria transmission in a region of savanna-forest mosaic, Haut-Ogooué, Gabon.

During the 2 years 1993 to 1995, an entomological survey was carried out in the savanna-forest area of Franceville, Gabon, investigating malaria transmission in one suburban district of Franceville (Akou) and in one rural village (Benguia). The biting rates of the Anopheles vectors were 10 times higher in the rural zone compared to the suburban zone. Anopheles funestus Giles was the predominant species in both zones followed by Anopheles gambiae s.l. Giles. The densities of Anopheles nili Theobald and Anopheles moucheti Evans were very low. In the suburban zone, transmission was maintained throughout the year by An. funestus and An. gambiae s.l., whereas in rural zones the secondary vectors An. nili and An. moucheti were also involved in transmission. Humans in a suburban setting received one infective bite per person every 4 days, whereas in the rural area the infective biting rate was 4 times higher. Considering each vector, the observed entomological inoculation rates (EIRs) were one infective bite per person every 6 and 17 days for An. funestus and An. gambiae s.l., respectively, at Akou. At Benguia, the EIRs were one infective bite per person every 2, 3, 6, and 19 days for the 4 An. funestus, An. gambiae s.l., An. nili, and An. moucheti, respectively. The predominance of An. funestus over An. gambiae s.l. and its high EIR make it the most important malaria vector in this region of Haut-Ogooué.

Aedes↗

Lack of malaria parasite transmission between apes and humans in Gabon.

The International Center for Medical Research (CIRMF) is located in an area highly endemic for malaria in southeastern Gabon, where humans and apes (gorillas and chimpanzees) are living in the same geographic area. The presence of the CIRMF primate center housing apes (59 chimpanzees and nine gorillas in 1994) within the city of Franceville provided an opportunity to investigate the capability of cross-transmission of malaria species from humans to apes. The main vector of human malaria, Anopheles gambiae, was found in the primate center and in a nearby populated area of Franceville. Despite high malaria transmission in humans of both Plasmodium falciparum and P. malariae (mean of 43% cumulative prevalence in schoolchildren), none of the apes were found infected with plasmodia during a six-month investigation. However, low antibody levels against sporozoite and blood stages of both P. falciparum and P. malariae were detected in a few chimpanzees and gorillas. These results demonstrate that only rarely would apes be bitten in the field by mosquitoes infected with human malaria parasites. In the case of infection proven by serology, we did not find any evidence that blood-stage malaria parasites were able to the gametocyte stage. The absence of any established malaria transmission cycle within the primate colony of CIRMF indicates that apes cannot be considered as animal reservoirs for human malaria parasites in this environment.

Adolescent↗

Impact of deltamethrin-impregnated bednets on biting rates of mosquitoes in Zaire.

In a rural area of Zaire, the whole population of a village was protected by deltamethrin-impregnated mosquitoes bednets. A similar village was observed as a control. Biting rates for mosquitoes were recorded in both villages. The principal man-biting species were Mansonia africana, Mansonia uniformis, and Aedes aegypti. In the village protected by the impregnated mosquito bednets, the number of Mansonia bites was reduced 96% indoors and at a lesser rate outdoors. Biting rates of Ae. aegypti dropped to 0 indoors, but the outdoor biting rate remained unchanged. It is concluded that the reduction in mosquito bites is not only caused by the repellent action of the deltamethrin but also by a reduction in mosquito numbers.

Animals↗

[Mosquito nets impregnated against malaria in Zaire].

On the Bateké plateau 60 km east of Kinshasa, Zaïre, where malaria is stable, three villages have been selected for a trial of malaria control using bednets impregnated with deltamethrin at 25 mg per square meter from February to November 1991. One village (3,000 inhabitants) has been provided 800 impregnated bednets and an other one (2,900 inhabitants) kept 800 non impregnated bednets. The third village (900 inhabitants) served as a control and has remained without nets. Anopheles gambiae was the main and nearly exclusive vector of malaria. Its biting density was reduced by 94% in the village protected by impregnated bednets and the inoculation rate dropped from 182 infective bites/man/year to 3.7 a decrease of 98%. The longevity of the vector expressed by its expectation of life decreased from 11.02 days to 3.64 days. In the village where inhabitants were protected by non impregnated nets, as well as in the control, the entomological indexes did not change. In the village protected with impregnated nets the malaria prevalence decreased by 50%, five months after the beginning of the experiment. The high parasitemia, above 10,000 and 20,000 parasites per mm3 decreased by 77% and 83% in the 0-7 year age group and by 67% and 65% in the 8-14 year group in the protected village. These high parasitemias are good markers of the clinical malaria risk. The experiment can be considered as very satisfactory on the point of view of public health.

Adolescent↗

[The culicidian fauna and its nuisance in Kinshasha (Zaire)].

A public health study to inventory bloodsucking mosquitoes was conducted in Kinshasa and its regions. 20 culicidian species were represented by 7 Anopheles, 6 Culex, 5 Aedes and 2 Mansonia. In general, the number of bites/man/night (b/m/n) was in average 141.5 of Cx. quinquefasciatus, 60.1 of Cx. antennatus, 21.1 of M. africana, 16.3 of An. gambiae and 7.7 of M. uniformis. The nuisance is different from region to other. Culex quinquefasciatus is the most abundant and aggressive species in the urban area with an average of 400 b/m/n. In certain suburban zones, Culex antennatus is predominant, with aggression on the order of 176.5 b/m/n. The Anopheles gambiae complex is predominant in the semi-rural zone at the periphery of the city with 26.05 b/m/n. Other mosquitoes are equally implicated in their aggression and nuisance to man, in particular, Mansonia africana, Mansonia uniformis and Aedes aegypti. A geographical distribution map has been established for the preponderant species in Kinshasa.

Animals↗

[Anopheles paludis: important vector of malaria in Zaire].

An entomological study was carried out on the transmission of malaria in the Bandundu region, Zaïre, during the dry season (July and August 1991). Five Anopheles species were recorded: Anopheles paludis, A. gambiae, A. funestus, A. moucheti and A. nili. A paludis was the dominant species and represents 55.1% of the total; the average number of A. paludis bites per man/day was 4.2. The sporozoite index was 6.2%; the inoculation rate due to A. paludis was h = 0.26, 1 infective bite each 4 days. A. paludis plays an important role with A. gambiae and is considered as one of the main vectors of malaria in this region.

Animals↗

Efficacy of Bacillus sphaericus against the malaria vector Anopheles gambiae and other mosquitoes in swamps and rice fields in Zaire.

The microbial control of Anopheles gambiae and other mosquitoes with a granular formulation of Bacillus sphaericus (Vectolex) was evaluated in rice fields and swamps, located around the suburban region of Kingabwa-village in Kinshasa, Zaíre. Ten treatment cycles with 15-day intervals were carried out with the same application rate, 10 kg/ha, during the dry season (May to September 1991). The treatments reduced larval populations of An. gambiae by 98% after 48 h, but repetitive applications were required every 15 days to maintain control. The persistence of B. sphaericus spores was more apparent in rice fields than in swamps. A significant reduction in nuisance biting by Culex quinquefasciatus and Mansonia uniformis was observed. For An. gambiae, a decrease of 13.6% in human biting was noted during the post-treatment period. The entomological inoculation rate was reduced from 0.238 to 0.143. The efficacy of B. sphaericus does not appear to offer outstanding potential for control of An. gambiae in rice fields and swamps and seems to be limited due to different factors tied to ecology and natural conditions in the fields.

Animals↗

[The Anopheles fauna and the transmission of human malaria in Kinshasa (Zaire)].

A longitudinal epidemiological study of malaria and its vectors was conducted in Kinshasa. 264 night-bite collections on human bait (1,056 man nights) and 384 collections of the house-resting fauna were carried out from April 1989 to October 1990. The anophelian fauna was identified and inventoried, 7 Anopheles species were found: Anopheles gambiae, An. funestus, An. paludis, An. hancocki, An. counstani, An. brunnipes, and An. nili. A single species, An. gambiae s. l. is responsible for the transmission of malaria, it represents 93.27% of the anopheline fauna. The average number of anophele bites man day was 16.28 bites/man/night, it varied between 1 b/m/n in urban area to 26.05 b/m/n in semi-rural area. The average of the sporozoite index for An. gambiae was 3.3%, but it varied from 0% in the urban area to 6.52% in the semi-rural area. The entomological inoculation rate (h) was 197 infective bites per year. This rate fluctuated from 1 infective bite each 128 nights in urban area to 1.7 infective night-bite in semi-rural area. Other epidemiological index were also determined: the level of daily survival rate (p = 8.75 days), the vectorial capacity of 17.97 and the Macdonald's stability 3.5 bites on man taken by a vector during its entire lifetime.

Animals↗

Field trials with Vectolex (Bacillus sphaericus) and Vectobac (Bacillus thuringiensis (H-14)) against Anopheles gambiae and Culex quinquefasciatus breeding in Zaire.

Under field conditions in Kinshasa, Zaire, an aqueous suspension of Bacillus thuringiensis (H-14), Vectobac (12-AS), lost most of its larvicidal activity at all concentrations after 48 h against Culex quinquefasciatus breeding in polluted gutter water and Anopheles gambiae breeding in clear water irrigation ponds. However, good control of Cx. quinquefasciatus was obtained using a granular formulation of B. sphaericus, Vectolex-G (ABG-6185), at concentrations of 10-30 kg/ha. High concentrations of Vectolex-G gave excellent control of An. gambiae breeding in irrigation ponds. The Vectobac-G was less active against An. gambiae than Vectolex-G, in spite of good dispersion of Vectobac-G particles.

Animals↗

Control of Culex pipiens by Bacillus sphaericus and role of nontarget arthropods in its recycling.

Bacillus sphaericus was used to control Culex pipiens breeding in a water treatment settling basin near Montpellier, France. Four treatments with 4 liters/ha (3.6 lb/acre) of commercially available B. sphaericus formulation (Vectolex) reduced the larval population of Cx. pipiens with 50-600 spores of B. sphaericus/ml recorded in the treated portions of the water plant 14 days following the last treatment. Natural recycling of the bacteria was shown to take place at the water surface where germination of spores was evidenced. The appearance of vegetative forms of B. sphaericus may be linked to the passage through larval guts of several filter-feeding arthropods.

Animals↗

[The recycling of waste water and mosquitoes].

Recycling waste water in the Achères complex (North-West Paris) is based on both sophisticated industrial techniques and simple agricultural methods. The sewage farms and settling pools provide suitable breeding sites for more than ten mosquito species. Aedes caspius is the major pest for the local population. Moreover Culex pipiens (anthropophilic form) breeds in the sewers of the neighbouring towns. Mosquito control is based early ground treatment of breeding sites. Temephos and fenotrothion are used against A. caspius. Spherimos (Bacillus sphaericus) is used to control C. pipiens. The two insecticides have no adverse effect on humans or the environment and Spherimos is harmless. Aedes pest have been virtually eliminated. Urban Culex control is generally good despite being performed by less well trained municipal employees. In the areas treated by the specialized team of the SIAAP, pest mosquitoes have disappeared. The techniques used in the Achères complex do not require sophisticated equipment. Thus, if adapted to local ecological, epidemiological and financial conditions they could be transferred to developing countries.

Aedes↗