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At least 1,207 records · Page 67Linked to original sources
PubMed2004

Predicting the risk of bluetongue through time: climate models of temporal patterns of outbreaks in Israel.

Determining the temporal relationship between climate and epidemics of Culicoides-borne viral disease may allow control and surveillance measures to be implemented earlier and more efficiently. In Israel, outbreaks of bluetongue (BT) have occurred almost annually since at least 1950, with severe episodes occurring periodically. In this paper, the authors model a twenty-year time-series of BT outbreaks in relation to climate. Satellite-derived correlates of low temperatures and high moisture levels increased the number of outbreaks per year. This is the first study to find a temporal relationship between the risk of Culicoides-borne disease and satellite-derived climate variables. Climatic conditions in the year preceding a BT episode, between October and December, coincident with the seasonal peak of vector abundance and outbreak numbers, appeared to be more importantthan spring or early summer conditions in the same year as the episode. Since Israel is an arid country, higher-than-average moisture levels during this period may increase the availability of breeding sites and refuges for adult Culicoides imicola vectors, while cooler-than-average temperatures will increase fecundity, offspring size and survival through adulthood in winter, which, in turn, increases the size of the initial vector population the following year. The proportion of variance in the annual BT outbreak time-series resulting from climate factors was relatively low, at around 20%. This was possibly due to temporal variation in other factors, such as viral incursions from surrounding countries and levels of herd immunity. Alternatively, since most BT virus (BTV) circulation in this region occurs silently, in resistant breeds of local sheep, the level of transmission is poorly correlated with outbreak notification so that strong relationships between BTV circulation and climate, if they exist, are obscured.

Animals↗
PubMed1984

Epidemiology of Trypanosoma cruzi in the oriental plains of Colombia.

Epidemiologic studies to define the domiciliary and extradomiciliary transmission cycles of Trypanosoma cruzi and Trypanosoma rangeli in the Oriental Plains of Colombia were conducted in the gallery forests near Carimagua and El Porvenir. One-hundred and seven palm trees belonging to nine genera were examined; triatomines were found in only three palm species, the leaves of which are locally used for roof thatching: 2/29 Maximiliana elegans, 1/7 Mauritia flexuosa and 7/7 Scheelea sp. Bugs were also found in 5/14 hollow Mauritia inhabited by bats, 4/21 bird nests and 1/4 armadillo burrows. Five species of triatomines were collected: Rhodnius prolixus was the most abundant, 192 of the total 207 (92%) collected; the bugs were found in Maximiliana and Mauritia but especially in Scheelea, and 8% were infected with T. cruzi and T. rangeli; Cavenicola pilosa and Triatoma maculata were found associated with bats; Psammolestes arthuri and Panstrongylus lignarius with bird nests and Panstrongylus geniculatus with armadillos. Although triatomine colonies were not found in human dwellings, flying adults of R. prolixus occasionally reached houses by their own locomotion and fed on man, but did not become established. Only 12 of 199 persons (6%) tested serologically were reactors to T. cruzi antigens and all 12 had lived in areas of domiciliary transmission elsewhere in the country, indicating that domiciliary transmission is not occurring in this region. Whether the presence of domiciliary R. prolixus in houses located in the ecologically altered piedmont of the oriental plains, a known area of domiciliary transmission of T. cruzi, is due to importation of domiciliary bugs from endemic areas or to the domiciliarization of wild R. prolixus remains to be determined.

Adolescent↗
PubMed2000

Virus-expressed, recombinant single-chain antibody blocks sporozoite infection of salivary glands in Plasmodium gallinaceum-infected Aedes aegypti.

Transgenic mosquitoes resistant to malaria parasites are being developed to test the hypothesis that they may be used to control disease transmission. We have developed an effector portion of an antiparasite gene that can be used to test malaria resistance in transgenic mosquitoes. Mouse monoclonal antibodies that recognize the circumsporozoite protein of Plasmodium gallinaceum can block sporozoite invasion of Aedes aegypti salivary glands. An anti-circumsporozoite monoclonal antibody, N2H6D5, whose corresponding heavy- and light-chain gene variable regions were engineered as a single-chain antibody construct, binds to P. gallinaceum sporozoites and prevents infection of Ae. aegypti salivary glands when expressed from a Sindbis virus. Mean intensities of sporozoite infections of salivary glands in mosquitoes expressing N2scFv were reduced as much as 99.9% when compared to controls.

Aedes↗
PubMed2001

[Aedes albopictus in bromeliads of anthropic environment in São Paulo State, Brazil].

OBJECTIVE: Aedes albopictus populations can breed in several kinds of containers, and its presence has also been reported in Bromeliaceae. The purpose of this study was to evaluate the epidemiological importance of the Bromeliaceae plants as potential breeding sites of Aedes albopictus and to document the associated Culicidae entomofauna found in this micro-habitat. METHODS: Collections of Culicidae larvae were carried out fortnightly in aquatic content of bromeliads during 1998 and 1999. Collections took place in urban and periurban areas of Ilhabela island and periurban area of Ilha Comprida island, Brazil. RESULTS: A total of 26,647 Culicidae larvae were collected at both study sites, 14,575 in the urban area and 10,987 in the periurban area of Ilhabela and the remaining 1,085 in the periurban area of Ilha Comprida. There was no statistical difference between the amount of larvae collected in urban and periurban areas of Ilhabela. Regarding the Ae. albopictus, there was found a higher frequency and amount of larvae in the urban area of Ilhabela, followed by the periurban area in the same site, whereas in the periurban area of Ilha Comprida, its presence was considered accidental, since it was reported only in the first three months. CONCLUSIONS: The results show that bromeliads, largely used in landscaping, may contribute to the spread of Ae. albopictus. The presence of this species in domesticated and domiciled bromeliads allows us to suggest that the Culicidae larva is part of the regional fauna and facilitate the contact between humans and etiological agents of the natural ecosystem.

Aedes↗
PubMedDate not supplied

[Notes on fleas (Siphonaptera) in plague foci on the Tay Nguyen plateau (Vietnam)].

The fleas of wild and commensal small mammals, domestic animals (dogs, cats) and free-living flea forms in houses have been collected in plague nidi of Tay Nguyen plate, Dak-Lak province, Vietnam. Pulex irritans, Ctenocephalides felis felis, Ct. felis orientis were found in the houses on dogs, cats and on the ground floor. Commensal rats in populated areas were infested by Xenopsylla cheopis and rarely by Lentistivalius klossi. The agricultural zone was inhabited by both home and wild animals such as commensal, savannah and forest-dwelling small mammals. The flea fauna of this zone is presented by X. cheopis and L. klossi. In the tropical forest surrounding villages four of the flea species were found: X. vexabilis, a specific parasite of the forest-dwelling rat Berylmys berdmorei, L. klossi found on six species of forest small mammals, Acropsylla girshami from Berylmys bowersii and Pariodontis subjugis from Hystrix brachyura. The agricultural zone is the most possible place of commensal and forest-dwelling small mammals contact, where the latter can get plague microbe.

Animals↗
PubMedDate not supplied

[Current state of epidemiologic surveillance of natural foci of plague of North Caucasus].

Information on the epizootic situation in plague in the natural foci of North Caucasus and on the influence of a number of anthropogenic and natural factors on this situation is presented. The data given in this work indicate that under the conditions of the anthropogenic transformation of landscapes the character of the epizootic manifestations of plague is changed and new factors, capable of aggravating epidemiological situation, appear. In addition, some other factors must be considered, such as the insufficient financing of reliable field surveys at present, the impossibility of making reliable epizootological studies due to causes of the social character (armed conflicts), thus making it impossible to evaluate, with a sufficient degree of reliability, the real epizootic state of a number of territories and, therefore, the risk of human infection. In this connection the necessity to carefully plan prophylactic measures and measures aimed at the localization and liquidation of the probable foci of infection arises.

Animals↗