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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

Prevalence of parasitemia (blood slide positive) by age, in three different epidemiological settings in Uganda.
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pone.0118901.g003: Prevalence of parasitemia (blood slide positive) by age, in three different epidemiological settings in Uganda.

Mentions: The prevalence of asexual parasitemia was significantly higher in Nagongera than the other two sites (p<0.001 for both comparisons), but was comparable in Walukuba and Kihihi, despite the difference in aEIR in the two sites “Table 2”. A similar pattern was seen for participants of all ages and children aged 2–10 years. Parasite prevalence increased with age, peaking by 11 years, and declining thereafter in all sites (Fig. 3). In the adjusted analysis, age was the only factor significantly associated with parasite prevalence “Table 4”. Although the parasite prevalence was substantially higher in Nagongera compared to the other two sites across all ages, the relationship between age and parasitemia was remarkably similar across all three sites. Increasing age was significantly associated with an increased odds of parasitemia up to 11 years of age (ORs ranging from 1.07 to 1.13 per 1 year increase in age) and then from 12–40 years increasing age was significantly associated with a decreased odds of parasitemia (ORs ranging from 0.89 to 0.92 per 1 year increase in age). Other factors, including gender, ITN use, and socioeconomic status were not significantly associated with parasitemia.


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 parasitemia (blood slide positive) 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.g003: Prevalence of parasitemia (blood slide positive) by age, in three different epidemiological settings in Uganda.
Mentions: The prevalence of asexual parasitemia was significantly higher in Nagongera than the other two sites (p<0.001 for both comparisons), but was comparable in Walukuba and Kihihi, despite the difference in aEIR in the two sites “Table 2”. A similar pattern was seen for participants of all ages and children aged 2–10 years. Parasite prevalence increased with age, peaking by 11 years, and declining thereafter in all sites (Fig. 3). In the adjusted analysis, age was the only factor significantly associated with parasite prevalence “Table 4”. Although the parasite prevalence was substantially higher in Nagongera compared to the other two sites across all ages, the relationship between age and parasitemia was remarkably similar across all three sites. Increasing age was significantly associated with an increased odds of parasitemia up to 11 years of age (ORs ranging from 1.07 to 1.13 per 1 year increase in age) and then from 12–40 years increasing age was significantly associated with a decreased odds of parasitemia (ORs ranging from 0.89 to 0.92 per 1 year increase in age). Other factors, including gender, ITN use, and socioeconomic status were not significantly associated with parasitemia.

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