Recent works carried out in west and central Africa resulted in numerous yellow fever virus isolations from sylvatic mosquitoes in the forest-savanna transitional zone. This virus was also obtained from monkeys, whereas studies on sequence and duration of the observed epizootics permitted a previsional approach of the yellow fever mechanisms in the same belt, the epidemiological importance of which was stressed ("emergence zone"). In the same course of research and publications, the prevalent part of the involved mosquitoes as virus-reservoirs was constantly emphasized ("reservoir-vector"). Recent investigations on transovarial transmission and yellow fever isolations from male mosquitoes caught in the field, provide decisive support to such a conception. It can explain that epizootics may be locally observed several years in succession, despite the fact that yellow fever virus circulation seems to be fundamentally of a dynamic character. Yellow fever virus was recently obtained from ticks and tick-eggs.

Africa↗

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[Arbovirus diseases in South America and Caribbean Islands (author's transl)].

Historically, yellow fever has dominated arboviral diseases in South America and the Caribbean and sylvatic cases still occur every year (more than 200 in 1979). The dengue, by the very large number of cases occurring in the area during successive epidemics--the most important being the last one in 1977-1978--is a serious problem for public health, an epidemic of hemorrhagic dengue being a constant threat. Encephalitides are the third syndrome of arboviral etiology observed in the South American subcontinent. Some which preferably attack horses have been known for a long time whereas the one due to the Rocio virus of an even graver prognosis, was recently discovered. These diseases present a large range of epidemiological forms. Dengue is an example of an urban illness transmitted from man to man through the mosquito, Aedes aegypti. But most of the viruses circulate between vectors and wild vertebrates in sylvatic cycle. For some viruses, both mechanisms can be involved. It is the case for Oropouche virus and yellow fever even if at present the urban form is the only recorded for the latter.

Animals↗

PubMedDate not supplied

[Isolation of the Lagos-bat virus in the Central African Republic].

The second reported isolate of Lagos-bat virus has been obtained from bats Micropterus pusillus caught in 1974 in the Central African Empire, thus extending the geographic area of this virus and adding another species of vertebrate host among its reservoirs.

Animals↗

PubMedDate not supplied

[Kedougou virus (Ar D14701): a new Arbovirus ("Flavivirus") isolated in Senegal (author's transl)].

Explore the source record for details and available documents.

Aedes↗

PubMedDate not supplied

[Isolation of a strain of Mokola virus in Cameroon (author's transl)].

A strain of Mokola virus has been isolated in Cameroon from a shrew (Crocidura sp.). In Nigeria, where the virus was isolated for the first time, two human cases with one death were reported. The possibility of transmission of this virus by the bite of an arthropod is discussed.

Animals↗

PubMedDate not supplied

[Yellow fever in Senegal from 1976 to 1980 (author's transl)].

The isolation of a YF strain in Kedougou (eastern region) in December 1976 from Aedes gr. furcifer taylori lead to a mass vaccination campaign in Senegal. In 1977, 67 strains were isolated from different mosquitoes (essentially A. luteocephalus and A. gr. furcifer taylori). Among these strains, 3 were isolated from males and this very important phenomenon might explain the virus conservation during the dry season. In 1978, 55 strains were isolated from mosquitoes of the same species, but not from males, and five from monkeys (E. patas and C. aethiops). But no increase of morbidity or mortality was observed in humans. In December 1978, a YF outbreak occurred in the Gambia with 271 suspect cases and 63 deaths; 2 strains were isolated from A. aegypti. In 1979, the epidemic seemed to have disappeared. Up to now, one single strain has been isolated from mosquitoes. But danger remains, and 3 YF human cases with 2 deaths were observed in Sine-Saloum, among French unvaccinated tourists.

Aedes↗

PubMedDate not supplied

[Malaria pattern in French Guyana (author's transl)].

Study of malaria pattern in French Guyana from 121.175 parasitological data collected from 1970 to 1979. -- General incidence is moderate (6,4 p. 1.000) and the mean plasmodial index is 2,7 p. 100. These paludometric data have much increased in 1973 (9,7 p. 1.000 and 5 p. 100) and 1979 (10,8 p. 1.000 and 4 p. 100). This is the consequence of two convergent factors both strengthening vectors activity: a flow of malaria infested immigrants and meteorologic conditions (lengthy drought). Plasmodial species involved are P. falciparum (84 p. 100) and P. vivax (15 p. 100), P. malariae having just a negligible role. However, it must be noted that from 1977, P. vivax, already prevalent in Oyapok, seems to become more frequently rated. -- True autochtonous malaria is localized in border areas; exchanges from both sides of the river are frequent and call for a regional coordination control. A part of these permanently active micro-foci, periodic rises observed are related, in almost all cases, to the arrival of malaria infested migrants. This is specially obvious in Cayenne Island where a sanitary control of migrants from endemic areas should be considered. -- A. (N.) darlingi is in French Guyana the almost sole vector, except for Upper-Oyapok where A. (K.) neivai is responsible for a malaria caused by Bromeliaceae. In exceptional conditions and localized foci A. (N.) braziliensis and less often A. (N.) aquasalis may be effective vectors. -- Anti-vector measures require an increased control at preimaginal stade. This public-health additional option calls for an integrated control: Cayenne Island conditions are assembled to design and evaluate a model.

Anopheles↗

PubMedDate not supplied

[Features of malaria in Guyana].

A paludometric study of the 1970-1979 decade in French Guyana, shows a 2.7% plasmodic index, with a mean incidence of 6.4 per 1,000 habitants and a very high prevalence of P. falciparum (84%). Anopheles darlingi, the principal vector, still remains sensitive to DDT after 30 years of insecticide utilisation. The autochthonous malaria occurs permanently in the bordering areas between Guyana and Brasil at the East and between Guyana and Surinam at the West. In the other parts of the country, in the Island of Cayenne particularly, seasonal epidemics appear during the dry months and are due to imported Plasmodium. Sanitary reglementation of immigration and an actualisation of the anti-vectorial programme control are proposed as prophylactic measures.

Anopheles↗