The seasonality of malaria transmission was studied in a Gambian village situated in an area where rice was cultivated. Observations were made during two dry seasons, when pump-fed irrigation was used to grow rice, and in the intervening rainy season, when rice was cultivated using a combination of irrigated and rain-fed paddies. Clinical episodes of malaria were mainly confined to the months during and soon after the rainy season. In the wet season the prevalence of parasitaemia was higher in febrile subjects than in afebrile controls but the reverse applied during the dry seasons. However, the biting rates of Anopheles gambiae complex mosquitoes in the two dry seasons (2.5 and 0.8 bites/child/night respectively) were greater than or similar to that in the rainy season (0.6 bites/child/night). The proportion of human bloodmeals (0.53 vs 0.75) and the survival of mosquitoes (parity rates of 0.41 vs 0.58) were both lower in the dry seasons than in the rains. The low prevalence of morbidity due to malaria in the dry season and the observed fall in the sporozoite rate may therefore have been due to a reduction in the vectorial capacity of the An. gambiae population. However, reduced transmission in the dry season may also have been due to the direct effect of high temperatures on the parasite in the vector.

Ability of Anopheles gambiae mosquitoes to transmit malaria during the dry and wet season in an area of irrigated rice cultivation in The Gambia / Lindsay, Sw; Wilkins, Ha; Zieler, Ha; Daly, Rj; Petrarca, Vincenzo; Byass, P.. - In: JOURNAL OF TROPICAL MEDICINE AND HYGIENE. - ISSN 0022-5304. - STAMPA. - 94:(1991), pp. 313-324.

Ability of Anopheles gambiae mosquitoes to transmit malaria during the dry and wet season in an area of irrigated rice cultivation in The Gambia.

PETRARCA, Vincenzo;
1991

Abstract

The seasonality of malaria transmission was studied in a Gambian village situated in an area where rice was cultivated. Observations were made during two dry seasons, when pump-fed irrigation was used to grow rice, and in the intervening rainy season, when rice was cultivated using a combination of irrigated and rain-fed paddies. Clinical episodes of malaria were mainly confined to the months during and soon after the rainy season. In the wet season the prevalence of parasitaemia was higher in febrile subjects than in afebrile controls but the reverse applied during the dry seasons. However, the biting rates of Anopheles gambiae complex mosquitoes in the two dry seasons (2.5 and 0.8 bites/child/night respectively) were greater than or similar to that in the rainy season (0.6 bites/child/night). The proportion of human bloodmeals (0.53 vs 0.75) and the survival of mosquitoes (parity rates of 0.41 vs 0.58) were both lower in the dry seasons than in the rains. The low prevalence of morbidity due to malaria in the dry season and the observed fall in the sporozoite rate may therefore have been due to a reduction in the vectorial capacity of the An. gambiae population. However, reduced transmission in the dry season may also have been due to the direct effect of high temperatures on the parasite in the vector.
01 Pubblicazione su rivista::01a Articolo in rivista
Ability of Anopheles gambiae mosquitoes to transmit malaria during the dry and wet season in an area of irrigated rice cultivation in The Gambia / Lindsay, Sw; Wilkins, Ha; Zieler, Ha; Daly, Rj; Petrarca, Vincenzo; Byass, P.. - In: JOURNAL OF TROPICAL MEDICINE AND HYGIENE. - ISSN 0022-5304. - STAMPA. - 94:(1991), pp. 313-324.
File allegati a questo prodotto
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/90721
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 33
  • Scopus 90
  • ???jsp.display-item.citation.isi??? 92
social impact