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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.


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Prevalence of anemia (hemoglobin < 11.0 g/dL) by age, in three different epidemiological settings in Uganda.
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pone.0118901.g002: Prevalence of anemia (hemoglobin < 11.0 g/dL) by age, in three different epidemiological settings in Uganda.

Mentions: Mean hemoglobin levels were generally high (> 12.0 g/dL) and severe anemia (hemoglobin < 8g/dL) was uncommon at all sites “Table 2”. The prevalence of anemia (hemoglobin < 11g/dL) was highest in Walukuba, the site with the lowest EIR “Table 2”. In children under-five, prevalence of anemia was significantly lower in Kihihi (29.5%), than in Walukuba (40.7%, p = 0.03) and Nagongera (49.4%, p<0.001). The probability of anemia was highest in children under-five, decreasing sharply until approximately 10 years of age at all 3 sites (Fig. 2). Considering all sites combined, the prevalence of anemia was 35.7% in those ≤ 5 years of age and 8.0% in those 6–40 years of age (p<0.001). In the adjusted analysis, the prevalence of anemia was most strongly associated with age “Table 3”. For children ≤ 5 years of age, the odds of anemia decreased greatly with increasing age at all the sites (ORs ranging from 0.47 to 0.70 per 1 year increase in age). For participants aged 6–40 years there was a more gradual decrease in the prevalence of anemia in Walukuba (OR 0.96 per 1 year increase) and Kihihi (OR 0.91 per 1 year increase in age). The association between anemia and other factors varied by site; in Kihihi and Nagongera, participants with parasitemia were significantly more likely to be anemic, but ITN use and other factors were not significantly associated. In Walukuba, participants who slept under an ITN the previous night were significantly less likely to be anemic.


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)

Prevalence of anemia (hemoglobin < 11.0 g/dL) 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.g002: Prevalence of anemia (hemoglobin < 11.0 g/dL) by age, in three different epidemiological settings in Uganda.
Mentions: Mean hemoglobin levels were generally high (> 12.0 g/dL) and severe anemia (hemoglobin < 8g/dL) was uncommon at all sites “Table 2”. The prevalence of anemia (hemoglobin < 11g/dL) was highest in Walukuba, the site with the lowest EIR “Table 2”. In children under-five, prevalence of anemia was significantly lower in Kihihi (29.5%), than in Walukuba (40.7%, p = 0.03) and Nagongera (49.4%, p<0.001). The probability of anemia was highest in children under-five, decreasing sharply until approximately 10 years of age at all 3 sites (Fig. 2). Considering all sites combined, the prevalence of anemia was 35.7% in those ≤ 5 years of age and 8.0% in those 6–40 years of age (p<0.001). In the adjusted analysis, the prevalence of anemia was most strongly associated with age “Table 3”. For children ≤ 5 years of age, the odds of anemia decreased greatly with increasing age at all the sites (ORs ranging from 0.47 to 0.70 per 1 year increase in age). For participants aged 6–40 years there was a more gradual decrease in the prevalence of anemia in Walukuba (OR 0.96 per 1 year increase) and Kihihi (OR 0.91 per 1 year increase in age). The association between anemia and other factors varied by site; in Kihihi and Nagongera, participants with parasitemia were significantly more likely to be anemic, but ITN use and other factors were not significantly associated. In Walukuba, participants who slept under an ITN the previous night were significantly less likely to be anemic.

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