Characteristics of Malaria Transmission in Kataragama, Sri Lanka: A Focus for Immuno-Epidemiological Studies

Mendis, Chandana; Gamage-Mendis, Asoka C.; Zoysa, A. P. K. De; Abhayawardena, T. A.; Carter, R.; Herath, P. R. J.; Mendis, Kamini

doi:10.4269/ajtmh.1990.42.298

Cited by 77 publications

(48 citation statements)

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“…That adults in our study remained negative for a longer period may be explained by a number of factors, one of which may be induction of an age-dependent acquired immunity. [38][39][40][41][42][43] The results of a study in Burkina Faso are similar to those presented herein. Esposito and others 20 reported that among 28-year-old adults, there was 0% P. falciparum prevalence at the beginning of the transmission season in June and approximately 10% at the end of the rainy season in November.…”

Section: Discussionsupporting

confidence: 78%

Identification of a subpopulation of immune Nigerian adult volunteers by antibodies to the circumsporozoite protein of Plasmodium falciparum.

Nwagwu

Anumudu²,

Sodeinde³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

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Abstract. Collections of human sera from malaria-endemic areas would be valuable for identifying and characterizing antigens as malaria vaccine candidates if the contributing serum donors' ability to resist infection were fully characterized. We prepared such a serum collection from 26 apparently immune Nigerian adults who failed to develop patent parasitemia for at least 20 weeks following a documented increase in antibodies to the circumsporozoite protein (CSP) from Plasmodium falciparum. Volunteers were evaluated five times per week for malaria symptoms and bimonthly for parasites by examining thick blood smears. The incidence rate over 13 months for the cohort was 42% (47 malaria-confirmed volunteers) and the risk of infection was 1.3 infections/year. Responses to CSP did not correlate with protection. Because antibody responses to antigens other than CSP may be associated with protection, the sera from these immune individuals may be useful for identifying and characterizing other potential malaria vaccine candidates.Malaria, particularly that caused by Plasmodium falciparum, remains one of the most serious diseases in the world, endangering infant and early childhood development in many tropical regions lacking the resources to implement thorough and widespread control programs. With the emergence of insecticide-resistant Anopheles mosquitoes and of drug-resistant P. falciparum, the prospect of human survival in malaria-endemic areas has become increasingly grave. Hope for successful control of malaria seems to lie in a concerted multi-pronged approach that includes environmental and continued vector control methods, combined with an appropriate use of anti-malarial drugs and continued efforts towards the development of malaria vaccines.Antigens from several developmental stages of P. falciparum are being evaluated for inclusion in a malaria vaccine, 1-11 with circumsporozoite protein (CSP) from the sporozoite stage and merozoite surface protein-1 (MSP-1) from the erythrocytic stage 12-17 receiving the most attention. Antibody responses to the central repeat region of the CSP have been studied in several malaria-endemic areas. Some investigators concluded that anti-CSP antibodies were protective, 18-20 while others did not. [21][22][23] Adult sera from malaria-endemic areas have been used in a number of clinical [24][25][26] studies to show that antibody can passively transfer protection against erythrocytic stage infections. Such sera have also found application in defining parasite antigens for inclusion in a malaria vaccine. 27-30 Sera such as these should be most valuable for the purpose of antigen discovery and characterization if the relative immune status of the donors were known.In the absence of detectable erythrocytic stage parasites, one method for assessing if a person living in an area of endemic malaria has been exposed to P. falciparum sporozoites is to measure boosting of the levels of the anti-CSP antibodies. Gordon and others 31 assumed that a two-fold or greater increase in antibody leve...

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Section: Discussionsupporting

confidence: 78%

Identification of a subpopulation of immune Nigerian adult volunteers by antibodies to the circumsporozoite protein of Plasmodium falciparum.

Nwagwu

Anumudu²,

Sodeinde³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

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“…The incidence of malaria is moderately seasonal, and the area is considered to be one of ''unstable'' but endemic malaria. The number of infectious bites per person per night is of the order of 0.001-0.01 (29), which compares to values of 0.1-1 in many areas of stable malaria in Africa (30). Most people in our study population have about one clinical attack per year, and generally 1-2% of the population are infected (at detectable levels) with either Plasmodium vivax or Plasmodium falciparum at any point in time (29).…”

Section: Methodsmentioning

confidence: 99%

“…The number of infectious bites per person per night is of the order of 0.001-0.01 (29), which compares to values of 0.1-1 in many areas of stable malaria in Africa (30). Most people in our study population have about one clinical attack per year, and generally 1-2% of the population are infected (at detectable levels) with either Plasmodium vivax or Plasmodium falciparum at any point in time (29). Epidemics of P. falciparum malaria used to occur at 7-to 10-year intervals (31), but since 1986, P. falciparum has persisted (32,33).…”

Section: Methodsmentioning

confidence: 99%

Quantifying genetic and nongenetic contributions to malarial infection in a Sri Lankan population

Mackinnon

Dissanayake

Rajakaruna

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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Explaining the causes of variation in the severity of malarial disease remains a major challenge in the treatment and control of malaria. Many factors are known to contribute to this variation, including parasite genetics, host genetics, acquired immunity, and exposure levels. However, the relative importance of each of these to the overall burden of malarial disease in human populations has not been assessed. Here, we have partitioned variation in the incidence of malarial infection and the clinical intensity of malarial disease in a rural population in Sri Lanka into its component causes by pedigree analysis of longitudinal data. We found that human genetics, housing, and predisposing systematic effects (e.g., sex, age, occupation, history of infections, village) each explained approximately 15% of the variation in the frequency of malarial infection. For clinical intensity of illness, 20% of the variation was explained by repeatable differences between patients, about half of which was attributable to host genetics. The other half was attributable to semipermanent differences among patients, most of which could be explained by known predisposing factors. Three percent of variation in clinical intensity was explained by housing, and an additional 7% was explained by current influences relating to infection status (e.g., parasitemia, parasite species). Genetic control of Plasmodium falciparum infections appeared to modulate the frequency and intensity of infections, whereas genetic control of Plasmodium vivax infections appeared to confer absolute susceptibility or refractoriness but not intensity of disease. Overall, the data show consistent, repeatable differences among hosts in their susceptibility to clinical disease, about half of which are attributable to host genes.

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“…Treatment for malaria was, in a reasonably high proportion (70%) of patients, based on a microscopic confirmation of the infection. This, viewed in light of our previous findings that the incidence of self-treatment for malaria among patients in Sri Lanka is quite low (Mendis et al 1990), suggests that the health system for case detection and treatment was reasonably good. In endemic areas of Sri Lanka, most malaria patients seek confirmation of a diagnosis of malaria before treatment, and self-treatment is rare; we believe that this is due in large measure to the generally high levels of literacy among the rural populations in Sri Lanka, resulting in relatively high expectations of health care.…”

Section: The Health System For Malaria In Generalmentioning

confidence: 60%

“…Several institutions at which traditional or indigenous systems of medicine such as Ayurvedha were practised were excluded from the study because our preliminary survey as well as previous sociological surveys conducted in this general area have indicated that as few as 0.12% of patients consult an indigenous medical practitioner for the treatment for malaria and other acute febrile illnesses (Mendis et al 1990).…”

Section: Area and Methodsmentioning

confidence: 99%

Optimizing the malaria data recording system through a study of case detection and treatment in Sri Lanka

Abeysekera

Wickremasinghe

Dissanayake

et al. 1997

Tropical Med Int Health

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The potential of using malaria incidence data routinely collected from endemic regions for disease control and research has increased with the availability of advanced computer‐based technologies, but will depend on the quality of the data itself. We report here an investigation into the relevance of malaria statistics provided by the routine data collection system in Moneragala, a rural malaria‐endemic region in Sri Lanka. All patients (n = 321) treated for malaria in 2 clusters of health care centres (HCCs) of both the private and the public sector in the administrative regions of Moneragala and Buttala Divisional Secretariat (D.S.). Divisions were studied in December 1995/January 1996. The catchment area of these HCCs included a population resident in 53 Grama Niladhari (GN) areas, the smallest administrative units of the country. Almost equal numbers of malaria patients were detected and treated at Government and private health care institutions, and in 70% of them treatment was based on a diagnosis confirmed by microscopy. The routine data recording system, however, included only statistics from the Government sector, and only of patients whose diagnosis was microscopically confirmed. In compiling data, the origin of a case of malaria is attributed to the D.S. Division in which the institution (at which the patient was treated) was located, rather than the area in which the patient was resident, which was inaccurate because 90% of malaria patients sought health care at institutions located closest to their residence, thus crossing administrative boundaries. It also led to a loss of resolution of spatial data because patients' addresses recorded at the Government HCCs to the village‐level are replaced in the statistics by the D.S. Division, which is a coarse spatial unit. Modifications to the system for malaria case recording needed to correct these anomalies are defined here. If implemented, these could result in major improvements to the quality of data, a valuable resource for the future of malaria control. The paper reiterates the call for the use of a standard spatial unit within a country to facilitate exchange of data among health and other sectors for the control of tropical diseases.

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Characteristics of Malaria Transmission in Kataragama, Sri Lanka: A Focus for Immuno-Epidemiological Studies

Cited by 77 publications

References 0 publications

Identification of a subpopulation of immune Nigerian adult volunteers by antibodies to the circumsporozoite protein of Plasmodium falciparum.

Identification of a subpopulation of immune Nigerian adult volunteers by antibodies to the circumsporozoite protein of Plasmodium falciparum.

Quantifying genetic and nongenetic contributions to malarial infection in a Sri Lankan population

Optimizing the malaria data recording system through a study of case detection and treatment in Sri Lanka

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