Transmission factors in malaria epidemiology and control in Africa

Coosemans, Marc; Wéry, M; Mouchet, Jean; Coriat, Pierre

doi:10.1590/s0074-02761992000700065

Cited by 11 publications

(11 citation statements)

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“…The densities of both species were similar and about 10‐fold lower than those of A. sundaicus in 2000. The very low parity rate of A. sundaicus supports the idea that the survival rate of this potential vector is too low to ensure effective malaria transmission (Coosemans et al. 1992).…”

Section: Discussionmentioning

confidence: 79%

Malaria epidemiology in a rural area of the Mekong Delta: a prospective community‐based study

Erhart

Thang

Bien³

et al. 2004

Tropical Med Int Health

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SummaryOver the past 10 years, the Mekong Delta region in Vietnam has experienced fast socio-economic development with subsequent changes in malaria vectors ecology. We conducted a 2-year prospective community-based study in a coastal rural area in the southern Mekong Delta to re-assess the malaria epidemiological situation and the dynamics of transmission. The incidence rate of clinical malaria, established on 558 individuals followed for 23 months by active case detection and biannual crosssectional surveys, was 2.6/100 person-years. Over the 2-year study period, the parasite rate and malaria seroprevalence (Plasmodium falciparum and P. vivax) decreased significantly from 2.4% to almost 0%. Passive case detection (PCD) of clinical cases and serological follow-up of newborns carried out in a larger population confirmed the low and decreasing trend of malaria transmission. The majority of fever cases were seen in the private sector and most were unnecessarily treated with antimalarials. Training and involvement of the private sector in detection of malaria cases would greatly improve the quality of health care and health information system. keywords malaria, Plasmodium falciparum, P. vivax, transmission, private health care providers, over-treatment, Mekong Delta

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Section: Discussionmentioning

confidence: 79%

Malaria epidemiology in a rural area of the Mekong Delta: a prospective community‐based study

Erhart

Thang

Bien³

et al. 2004

Tropical Med Int Health

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“…sundaicus (up to 190 bites/man/night) in the Mekong delta, but none contained CSP. Potential malaria vectors occurring at high densities have often a survival rate which is too low for assuring effective malaria transmission (Coosemans et al. 1992).…”

Section: Discussionmentioning

confidence: 99%

Malaria transmission and major malaria vectors in different geographical areas of Southeast Asia

Trung

Bortel

Sochantha

et al. 2004

Tropical Med Int Health

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Summary During the last decade, major progress in malaria control has been achieved in Vietnam, Laos and Cambodia. However, malaria is still a potentially fatal disease in some hilly‐forested areas and continues to be endemic in a few coastal foci. To estimate the risk that stems from the major vectors after a decade of intensive malaria control, an entomological study based on human landing collections was conducted between April 1998 and November 2000 in six study villages (four in Vietnam, one in Cambodia and one in Laos) located in different physio‐geographical areas. Five villages were selected in places where new cases of malaria still occurred. In the sixth village, in the northern hilly area of Vietnam, no case of malaria was detected during the past 3 years. In three study villages of the hilly forested areas of Cambodia and central Vietnam, Anopheles dirus A still played an important role in malaria transmission and maintain perennial transmission inside the villages despite its low density. Anopheles minimus A was found in all study villages except in the southern coastal village of Vietnam. Its role in malaria transmission, however, varied between localities and surveys. In one study village of central Vietnam it was almost absent (one specimen collected over 480 man nights), and in another village sporozoite positive specimens (2.8%) were only observed during the first two surveys whereas this species disappeared from the collections from November 1998 onwards (six surveys: 360 man nights). In the northern study site An. minimus A and C were found in all collections, but no local malaria transmission occurred. However, the constant presence of these two species associated with a high longevity (parous rate up around 80% and 65%, respectively), suggests that transmission can occur at almost any time if parasite reservoirs are reintroduced in the area. The proper management of malaria cases and population movement is, therefore, important to prevent outbreaks and the reintroduction of malaria in northern Vietnam. In the study site of the Mekong delta, An. sundaicus occurred at high densities (up to 190 bites/man/night). The recent changes in land use from rice cultivation to shrimp farming probably explains the increase of this brackish water breeding species during the study period. However, none of the 11 002 specimens was positive for Plasmodium circumsporozoite protein (CSP). The relative low survival rate as estimated by the parous rate (around 47 %) may reflect its low vectorial status that could explain the very low malaria incidence (1.9 case/100 persons/year) in this study site. A calculated sporozoite rate of maximum 1/300 000 is enough to explain this low malaria incidence. Despite the successes in malaria control, the vector An. dirus A continues to play an important role in malaria transmission, whereas An. minimus A showed temporal and spatial variation in its role as vector. The role of An. sundaicus as vector could not be confirmed because of the low incidence in the coastal study villa...

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“…The immune system's first lines of defence against infection are the anatomical and physical barriers of our body' surfaces, and parasites have developed a number of active approaches to overcome these barriers. Many parasites, both protozoa and helminths , are transmitted by insect vectors that use needle‐like proboscises to inject the parasite through the host's skin. Other parasites directly penetrate the skin or the intestinal mucosa .…”

Section: Initiation and Escalation Of The Immune Responsementioning

confidence: 99%

Protection and pathology during parasite infection: IL‐10 strikes the balance

Redpath

Fonseca

Perona-Wright

2014

Parasite Immunology

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SUMMARYThe host response to infection requires an immune response to be strong enough to control the pathogen but also restrained, to minimize immune-mediated pathology. The conflicting pressures of immune activation and immune suppression are particularly apparent in parasite infections, where co-evolution of host and pathogen has selected many different compromises between protection and pathology. Cytokine signals are critical determinants of both protective immunity and immunopathology, and, in this review, we focus on the regulatory cytokine IL-10 and its role in protozoan and helminth infections. We discuss the sources and targets of IL-10 during parasite infection, the signals that initiate and reinforce its action, and its impact on the invading parasite, on the host tissue, and on coincident immune responses.

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Transmission factors in malaria epidemiology and control in Africa

Cited by 11 publications

References 0 publications

Malaria epidemiology in a rural area of the Mekong Delta: a prospective community‐based study

Malaria epidemiology in a rural area of the Mekong Delta: a prospective community‐based study

Malaria transmission and major malaria vectors in different geographical areas of Southeast Asia

Protection and pathology during parasite infection: IL‐10 strikes the balance

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