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Factors associated with malaria parasitemia, anemia and serological responses in a spectrum of epidemiological settings in Uganda.

Yeka A, Nankabirwa J, Mpimbaza A, Kigozi R, Arinaitwe E, Drakeley C, Greenhouse B, Kamya MR, Dorsey G, Staedke SG - PLoS ONE (2015)

Bottom Line: Prevalence of anemia (hemoglobin < 11.0 g/dL) was significantly higher in Walukuba (18.9%) and Nagongera (17.4%) than in Kihihi (13.1%), and was strongly associated with decreasing age for those ≤ 5 years at all sites.Parasite prevalence was significantly higher in Nagongera (48.3%) than in Walukuba (12.2%) and Kihihi (12.8%), and significantly increased with age to 11 years, and then significantly decreased at all sites.AMA-1 seroconversion rates strongly correlated with transmission intensity, while serological responses to MSP-119 did not.

View Article: PubMed Central - PubMed

Affiliation: Makerere University School of Public Health, College of Health Sciences, Kampala, Uganda; Infectious Diseases Research Collaboration, Kampala, Uganda.

ABSTRACT

Background: Understanding the current epidemiology of malaria and the relationship between intervention coverage, transmission intensity, and burden of disease is important to guide control activities. We aimed to determine the prevalence of anemia, parasitemia, and serological responses to P. falciparum antigens, and factors associated with these indicators, in three different epidemiological settings in Uganda.

Methods and findings: In 2012, cross-sectional surveys were conducted in 200 randomly selected households from each of three sites: Walukuba, Jinja district (peri-urban); Kihihi, Kanungu district (rural); and Nagongera, Tororo district (rural) with corresponding estimates of annual entomologic inoculation rates (aEIR) of 3.8, 26.6, and 125.0, respectively. Of 2737 participants, laboratory testing was done in 2227 (81.4%), including measurement of hemoglobin, parasitemia using microscopy, and serological responses to P. falciparum apical membrane antigen 1 (AMA-1) and merozoite surface protein 1, 19 kilodalton fragment (MSP-119). Analysis of laboratory results was restricted to 1949 (87.5%) participants aged ≤ 40 years. Prevalence of anemia (hemoglobin < 11.0 g/dL) was significantly higher in Walukuba (18.9%) and Nagongera (17.4%) than in Kihihi (13.1%), and was strongly associated with decreasing age for those ≤ 5 years at all sites. Parasite prevalence was significantly higher in Nagongera (48.3%) than in Walukuba (12.2%) and Kihihi (12.8%), and significantly increased with age to 11 years, and then significantly decreased at all sites. Seropositivity to AMA-1 was 53.3% in Walukuba, 63.0% in Kihihi, and 83.7% in Nagongera and was associated with increasing age at all sites. AMA-1 seroconversion rates strongly correlated with transmission intensity, while serological responses to MSP-119 did not.

Conclusion: Anemia was predominant in young children and parasitemia peaked by 11 years across 3 sites with varied transmission intensity. Serological responses to AMA-1 appeared to best reflect transmission intensity, and may be a more accurate indicator for malaria surveillance than anemia or parasitemia.

No MeSH data available.


Related in: MedlinePlus

Seroconversion to AMA-1and MSP-119 by age, in three different epidemiological settings in Uganda.
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pone.0118901.g004: Seroconversion to AMA-1and MSP-119 by age, in three different epidemiological settings in Uganda.

Mentions: The antibody response to AMA-1, whether evaluated as seroprevalence, titer, or seroconversion rate, increased with increasing transmission intensity “Table 2”. Seroprevalences to AMA-1 were 53.3% in Walukuba, 63.0% in Kihihi and 83.7% in Nagongera (p<0.001 for all comparisons). AMA-1 seroconversion rates were 0.10, 0.17, and 0.42, which, based on prior calibration, corresponded to calculated aEIRs of 3, 9, and 121 for Walukuba, Kihihi, and Nagongera, respectively. Peak seroprevalences were proportionate to the level of transmission intensity and the age at which the peak was reached was inversely proportional to transmission intensity (Fig. 4). In the adjusted analysis, increasing age was associated with increased odds of seropositivity to AMA-1 up to 10 years of age at all three sites with the strength of this association increasing with increasing transmission intensity “Table 5”. In Nagongera, seropositivity to AMA-1 peaked by 10 years of age but continued to increase significantly from 11–20 years of age in Walukuba and Kihihi. Parasitemia was strongly associated with AMA-1 seropositivity at all sites “Table 5”. In Walukuba only, gender and socioeconomic status were also significantly associated with AMA-1 seropositivity, with significantly higher odds for females, and significantly lower odds for those participants of highest socioeconomic status.


Factors associated with malaria parasitemia, anemia and serological responses in a spectrum of epidemiological settings in Uganda.

Yeka A, Nankabirwa J, Mpimbaza A, Kigozi R, Arinaitwe E, Drakeley C, Greenhouse B, Kamya MR, Dorsey G, Staedke SG - PLoS ONE (2015)

Seroconversion to AMA-1and MSP-119 by age, in three different epidemiological settings in Uganda.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4358889&req=5

pone.0118901.g004: Seroconversion to AMA-1and MSP-119 by age, in three different epidemiological settings in Uganda.
Mentions: The antibody response to AMA-1, whether evaluated as seroprevalence, titer, or seroconversion rate, increased with increasing transmission intensity “Table 2”. Seroprevalences to AMA-1 were 53.3% in Walukuba, 63.0% in Kihihi and 83.7% in Nagongera (p<0.001 for all comparisons). AMA-1 seroconversion rates were 0.10, 0.17, and 0.42, which, based on prior calibration, corresponded to calculated aEIRs of 3, 9, and 121 for Walukuba, Kihihi, and Nagongera, respectively. Peak seroprevalences were proportionate to the level of transmission intensity and the age at which the peak was reached was inversely proportional to transmission intensity (Fig. 4). In the adjusted analysis, increasing age was associated with increased odds of seropositivity to AMA-1 up to 10 years of age at all three sites with the strength of this association increasing with increasing transmission intensity “Table 5”. In Nagongera, seropositivity to AMA-1 peaked by 10 years of age but continued to increase significantly from 11–20 years of age in Walukuba and Kihihi. Parasitemia was strongly associated with AMA-1 seropositivity at all sites “Table 5”. In Walukuba only, gender and socioeconomic status were also significantly associated with AMA-1 seropositivity, with significantly higher odds for females, and significantly lower odds for those participants of highest socioeconomic status.

Bottom Line: Prevalence of anemia (hemoglobin < 11.0 g/dL) was significantly higher in Walukuba (18.9%) and Nagongera (17.4%) than in Kihihi (13.1%), and was strongly associated with decreasing age for those ≤ 5 years at all sites.Parasite prevalence was significantly higher in Nagongera (48.3%) than in Walukuba (12.2%) and Kihihi (12.8%), and significantly increased with age to 11 years, and then significantly decreased at all sites.AMA-1 seroconversion rates strongly correlated with transmission intensity, while serological responses to MSP-119 did not.

View Article: PubMed Central - PubMed

Affiliation: Makerere University School of Public Health, College of Health Sciences, Kampala, Uganda; Infectious Diseases Research Collaboration, Kampala, Uganda.

ABSTRACT

Background: Understanding the current epidemiology of malaria and the relationship between intervention coverage, transmission intensity, and burden of disease is important to guide control activities. We aimed to determine the prevalence of anemia, parasitemia, and serological responses to P. falciparum antigens, and factors associated with these indicators, in three different epidemiological settings in Uganda.

Methods and findings: In 2012, cross-sectional surveys were conducted in 200 randomly selected households from each of three sites: Walukuba, Jinja district (peri-urban); Kihihi, Kanungu district (rural); and Nagongera, Tororo district (rural) with corresponding estimates of annual entomologic inoculation rates (aEIR) of 3.8, 26.6, and 125.0, respectively. Of 2737 participants, laboratory testing was done in 2227 (81.4%), including measurement of hemoglobin, parasitemia using microscopy, and serological responses to P. falciparum apical membrane antigen 1 (AMA-1) and merozoite surface protein 1, 19 kilodalton fragment (MSP-119). Analysis of laboratory results was restricted to 1949 (87.5%) participants aged ≤ 40 years. Prevalence of anemia (hemoglobin < 11.0 g/dL) was significantly higher in Walukuba (18.9%) and Nagongera (17.4%) than in Kihihi (13.1%), and was strongly associated with decreasing age for those ≤ 5 years at all sites. Parasite prevalence was significantly higher in Nagongera (48.3%) than in Walukuba (12.2%) and Kihihi (12.8%), and significantly increased with age to 11 years, and then significantly decreased at all sites. Seropositivity to AMA-1 was 53.3% in Walukuba, 63.0% in Kihihi, and 83.7% in Nagongera and was associated with increasing age at all sites. AMA-1 seroconversion rates strongly correlated with transmission intensity, while serological responses to MSP-119 did not.

Conclusion: Anemia was predominant in young children and parasitemia peaked by 11 years across 3 sites with varied transmission intensity. Serological responses to AMA-1 appeared to best reflect transmission intensity, and may be a more accurate indicator for malaria surveillance than anemia or parasitemia.

No MeSH data available.


Related in: MedlinePlus