Malaria seroepidemiology: comparison between indirect fluorescent antibody test and enzyme immunoassay using bloodspot eluates

Carvalho, Maria Esther de; Ferreira, Marcelo Urbano; Souza, Márcia Regina Delgado de; Ninomia, Regina Tomoko; Matos, Guiomar Fonseca; Camargo, Luís Marcelo Aranha; Ferreira, Cláudio Santos

doi:10.1590/s0074-02761992000200006

Cited by 18 publications

(11 citation statements)

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“…Later studies using crude or recombinant antigens from P. falciparum and/or P. vivax have confirmed these findings in Africa [19]–[21], Asia [22],[23] and South America, including Brazil [12] [24]–[30].…”

Section: Introductionmentioning

confidence: 81%

Serologically Defined Variations in Malaria Endemicity in Pará State, Brazil

et al. 2014

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BackgroundMeasurement of malaria endemicity is typically based on vector or parasite measures. A complementary approach is the detection of parasite specific IgG antibodies. We determined the antibody levels and seroconversion rates to both P. vivax and P. falciparum merozoite antigens in individuals living in areas of varying P. vivax endemicity in Pará state, Brazilian Amazon region.Methodology/Principal FindingsThe prevalence of antibodies to recombinant antigens from P. vivax and P. falciparum was determined in 1,330 individuals. Cross sectional surveys were conducted in the north of Brazil in Anajás, Belém, Goianésia do Pará, Jacareacanga, Itaituba, Trairão, all in the Pará state, and Sucuriju, a free-malaria site in the neighboring state Amapá. Seroprevalence to any P. vivax antigens (MSP1 or AMA-1) was 52.5%, whereas 24.7% of the individuals were seropositive to any P. falciparum antigens (MSP1 or AMA-1). For P. vivax antigens, the seroconversion rates (SCR) ranged from 0.005 (Sucuriju) to 0.201 (Goianésia do Pará), and are strongly correlated to the corresponding Annual Parasite Index (API). We detected two sites with distinct characteristics: Goianésia do Pará where seroprevalence curve does not change with age, and Sucuriju where seroprevalence curve is better described by a model with two SCRs compatible with a decrease in force of infection occurred 14 years ago (from 0.069 to 0.005). For P. falciparum antigens, current SCR estimates varied from 0.002 (Belém) to 0.018 (Goianésia do Pará). We also detected a putative decrease in disease transmission occurred ∼29 years ago in Anajás, Goianésia do Pará, Itaituba, Jacareacanga, and Trairão.ConclusionsWe observed heterogeneity of serological indices across study sites with different endemicity levels and temporal changes in the force of infection in some of the sites. Our study provides further evidence that serology can be used to measure and monitor transmission of both major species of malaria parasite.

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Section: Introductionmentioning

confidence: 81%

Serologically Defined Variations in Malaria Endemicity in Pará State, Brazil

et al. 2014

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“…15 Titers ³ 16 were considered positive, because this cut-off value resulted in the best combination of sensitivity and specificity (i.e., highest diagnostic efficiency) when 108 negative control sera, 45 P. falciparum -positive control sera, and 48 P. vivax -positive control sera were analyzed. 14 By applying this cut-off titer, our indirect fluorescent antibody test had a sensitivity of 96% and a specificity of 98% for anti-P. falciparum antibodies and a sensitivity of 93% and a specificity of 96% for anti-P. vivax antibodies (data from Carvalho and others 14 ). When comparing paired samples, we defined exposure to malaria between blood draws to have occurred if 1) IgG antibodies were undetectable (below the cut-off titer) in the first sample and detectable in the second sample, or 2) there was an increase of 4-fold greater IgG antibody titers between the first and second blood draw.…”

Section: Methodsmentioning

confidence: 91%

“…To infer the occurrence of malarial infections between cross-sectional surveys, we compared titers of IgG antibodies to P. falciparum and P. vivax, measured by indirect fluorescent antibody test, in paired samples collected from the same subjects during Travel 1 and Travel 2. The assay protocol is described in detail elsewhere, 14 with P. falciparum and P. vivax antigens prepared directly from the blood of infected subjects. 15 Titers ³ 16 were considered positive, because this cut-off value resulted in the best combination of sensitivity and specificity (i.e., highest diagnostic efficiency) when 108 negative control sera, 45 P. falciparum -positive control sera, and 48 P. vivax -positive control sera were analyzed.…”

Section: Methodsmentioning

confidence: 99%

“…Although P. vivax infections predominated during the cross-sectional surveys, seroconversion rates between surveys were higher for anti-P. falciparum than anti-P. vivax antibodies. Because the sensitivity of the method used for antibody detection may vary according to the species, 14 we suggest that between-species comparisons of seroconversion rates may be inappropriate. We also tested whether the exposure to P. vivax and P. falciparum, as inferred from the analysis of paired antibody titers, differed between males and females in the study area.…”

Section: Prevalence Of Malarial Infection and Diseasementioning

confidence: 99%

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Age-Dependent Acquisition of Protective Immunity to Malaria in Riverine Populations of the Amazon Basin of Brazil

Ladeia‐Andrade¹,

Ferreira²,

Carvalho³

et al. 2009

The American Journal of Tropical Medicine and Hygiene

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105

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Five community-based cross-sectional surveys of malaria morbidity and associated risk factors in remote riverine populations in northwestern Brazil showed average parasite rates of 4.2% (thick-smear microscopy) and 14.4% (polymerase chain reaction [PCR]) in the overall population, with a spleen rate of 13.9% among children 2-9 years of age. Plasmodium vivax was 2.8 times more prevalent than P. falciparum, with rare instances of P. malariae and mixed-species infections confirmed by PCR; 9.6% of asymptomatic subjects had parasitemias detected by PCR. Low-grade parasitemia detected by PCR only was a risk factor for anemia, after controlling for age and other covariates. Although clinical and subclinical infections occurred in all age groups, the risk of infection and disease decreased significantly with increasing age, after adjustment for several covariates in multilevel logistic regression models. These findings suggest that the continuous exposure to hypo- or mesoendemic malaria may induce significant anti-parasite and anti-disease immunity in native Amazonians.

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“…However, determination of antimalarial antibodies by ELISA has been shown to be a potentially useful epidemiological tool [11, 12]. For example, antibodies to the circumsporozoite antigen have been associated with transmission intensity [10] and with cumulative (age related) exposure to infection in both Brazil [13] and Sri Lanka [14]. In addition, serological data are relatively simple to collect: blood processed or blood spots collected.…”

Section: Resultsmentioning

confidence: 99%