Reliable assessment of malaria prevalence through village clinics

Fox, Emile; Strickland, G. Thomas; Sarwar, Mohammad; Mohammad, Shamim; Zafar-Latif, A.; Khaliq, Amir A.

doi:10.1016/0035-9203(87)90300-2

Cited by 5 publications

(6 citation statements)

References 2 publications

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“…As with the present study, the weakest correlation was also reported for TPR among individuals aged � 15 years in the moderate (rho = 0.32) and high transmission areas (rho = 0.01) [43]. A much earlier study, outside of Africa, in Punjab, Pakistan, found a stronger positive correlation (rho = 0.97) between clinic slide positivity data and community survey data from four villages compared at three different periods of observation [42].…”

Section: Discussionsupporting

confidence: 66%

“…Several examples of the use of routine TPR data exist to understand the sub-national variations in malaria risk [26][27][28][29][30], at smaller spatial scales to define temporal trends [31][32][33][34][35][36][37], or intervention impact [38][39][40][41]. However, there have been few direct comparisons between community-based parasite prevalence and facility-based TPR [24,42,43]. Here the relationship between time-space matched TPR at health facilities and community-based prevalence of infection on the Kenyan coast was examined.…”

Section: Introductionmentioning

confidence: 99%

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The relationship between facility-based malaria test positivity rate and community-based parasite prevalence

et al. 2020

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Introduction Malaria surveillance is a key pillar in the control of malaria in Africa. The value of using routinely collected data from health facilities to define malaria risk at community levels remains poorly defined. Methods Four cross-sectional parasite prevalence surveys were undertaken among residents at 36 enumeration zones in Kilifi county on the Kenyan coast and temporally and spatially matched to fever surveillance at 6 health facilities serving the same communities over 12 months. The age-structured functional form of the relationship between test positivity rate (TPR) and community-based parasite prevalence (PR) was explored through the development of regression models fitted by alternating the linear, exponential and polynomial terms for PR. The predictive ranges of TPR were explored for PR endemicity risk groups of control programmatic value using cutoffs of low (PR <5%) and high (PR � 30%) transmission intensity. Results Among 28,134 febrile patients encountered for malaria diagnostic testing in the health facilities, 12,143 (43.2%: 95% CI: 42.6%, 43.7%) were positive. The overall community PR was 9.9% (95% CI: 9.2%, 10.7%) among 6,479 participants tested for malaria. The polynomial model was the best fitting model for the data that described the algebraic relationship between TPR and PR. In this setting, a TPR of � 49% in all age groups corresponded to an age-standardized PR of � 30%, while a TPR of < 40% corresponded to an age-standardized PR of < 5%. Conclusion A non-linear relationship was observed between the relative change in TPR and changes in the PR, which is likely to have important implications for malaria surveillance programs,

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Section: Discussionsupporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

The relationship between facility-based malaria test positivity rate and community-based parasite prevalence

et al. 2020

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“…9,10,33 The results of this study indicate that health facility-derived serological, parasitological, and molecular measures can detect differences in transmission intensity at a small geographical scale and are sensitive to seasonal changes. These findings suggest that health facility surveys are able to provide a reasonable measure of community-level transmission, are capable of delineating areas of high or low malaria transmission and that the use of serology and PCR added useful information to assessment of transmission levels in the sampled populations that would have been missed if sampling focused solely on those cases suspected of having malaria.…”

Section: Discussionmentioning

confidence: 78%

High Levels of Asymptomatic and Subpatent Plasmodium falciparum Parasite Carriage at Health Facilities in an Area of Heterogeneous Malaria Transmission Intensity in the Kenyan Highlands

Stresman¹,

Stevenson²,

Ngwu³

et al. 2014

The American Journal of Tropical Medicine and Hygiene

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Abstract. In endemic settings, health facility surveys provide a convenient approach to estimating malaria transmission intensity. Typically, testing for malaria at facilities is performed on symptomatic attendees, but asymptomatic infections comprise a considerable proportion of the parasite reservoir. We sampled individuals attending five health facilities in the western Kenyan highlands. Malaria prevalence by rapid diagnostic test (RDT) was 8.6-32.9% in the health facilities. Of all polymerase chain reaction-positive participants, 46.4% (95% confidence interval [95% CI] = 42.6-50.2%) of participants had infections that were RDT-negative and asymptomatic, and 55.9% of those infections consisted of multiple parasite clones as assessed by merozoite surface protein-2 genotyping. Subpatent infections were more common in individuals reporting the use of non-artemisinin-based antimalarials in the 2 weeks preceding the survey (odds ratio = 2.49, 95% CI = 1.04-5.92) compared with individuals not reporting previous use of antimalarials. We observed a large and genetically complex pool of subpatent parasitemia in the Kenya highlands that must be considered in malaria interventions.

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“…In both cases, these biases would work against the principal patterns presented here. Fox and Strickland (1989) noted that their conclusions relied on a prior demonstration by Fox et al (1987) that the overall and species-specific prevalences found in surveys of village clinic attendees sufficiently mimicked those in community surveys. Because 16 of the P. falciparum-P. vivax studies used here acquired data either through clinics or with other techniques that collect blood only in cases of self-reported recent fevers, neither of which are random surveys of the population, we were concerned that the higher overall prevalence in these studies might bias our findings.…”

Section: Resultsmentioning

confidence: 99%

Mixed-Species Plasmodium Infections of Humans

Wh²

1997

The Journal of Parasitology

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We analyzed point-prevalence data from 35 recent studies of human populations in which Plasmodium falciparum and one other Plasmodium species were the reported causes of malaria infections. For the P. falciparum-Plasmodium vivax pair, higher overall prevalence in a human population is associated with fewer mixed-species infections than expected on the basis of the product of individual species prevalences. This is not true for P. falciparum-Plasmodium malariae.Our current understanding of parasite communities rests on several decades of fruitful studies of helminths (Noble, 1960;Schad, 1963;Kennedy, 1975;Scott and Gibbs, 1986;Stock and Holmes, 1988;Esch et al., 1990;Fernandez and Esch, 1991; Booth and Bundy, 1992;Kennedy and Bush, 1992). Many of the ecological and evolutionary insights from these pioneering studies could be tested among parasitic protists as well, building from analyses of relatively static, simple patterns among a few congeners toward those of dynamic interactions among multiple genera. Among helminths, for instance, Dobson (1985Dobson ( , 1990 Dobson and Roberts, 1994) has emphasized that aggregated intraspecific distributions may diminish interspecific competition, and Font (1991, 1994;Lotz et al., 1995) have stressed that species rarity and recruitment may modulate patterns of interspecific association.Four species of Plasmodium cause human malaria, P. falciparum, P. malariae, P. ovale, and P. vivax. Sympatric combinations of these species occur in human populations and within infected individuals. Various phenomena associated with species co-occurrence have been studied as such for more than a century, e.g., Thayer and Hewetson (1895), since an era in which the very existence of more than one species was subject to debate. Biogeographic anomalies such as the absence of P. vivax and presence of P. ovale in West Africa and the spotty worldwide distribution of P. malariae have periodically attracted intense interest (see Molineaux, 1988), as have the frequencies of species co-occurrence within individuals and the possible correlates of mixed-species infections. This paper focusses on the latter 2 topics, particularly in those human populations in which recent reports suggest that only P. falciparum and 1 other Plasmodium species co-occur.In a massive survey of Plasmodium species prevalence in humans, Knowles and White (1930) recorded mixed-species infections at various frequencies at various sites on all 6 inhabited continents and noted that particular species combinations were often seasonal. They complained that mixed-species infections were often underreported, and demonstrated the phenomenon in a test of microscopists. Cohen's (1973) analysis of the epidemiological literature concluded that deficits in the reported prevalence of mixed-species infections were not wholly artifactual, but common, often statistically significant phenomena with a previously unsuspected biological basis in heterologous immunity. His hypothesis was later extended to encompass the seasonal species pa...

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Reliable assessment of malaria prevalence through village clinics

Cited by 5 publications

References 2 publications

The relationship between facility-based malaria test positivity rate and community-based parasite prevalence

The relationship between facility-based malaria test positivity rate and community-based parasite prevalence

High Levels of Asymptomatic and Subpatent Plasmodium falciparum Parasite Carriage at Health Facilities in an Area of Heterogeneous Malaria Transmission Intensity in the Kenyan Highlands

Mixed-Species Plasmodium Infections of Humans

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