Plasmodiumdiversity in non-malaria individuals from the Bioko Island in Equatorial Guinea (West Central-Africa)

Guerra-Neira, Ana; Rubio, José Miguel; Royo, Jesús Roche; Cano, Jorge; Auñón, Antonio Sarrión; Berzosa, Pedro; Llanes, Agustín Benito

doi:10.1186/1476-072x-5-27

Cited by 29 publications

(17 citation statements)

References 10 publications

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“…Among the factors associated with mixed malaria infections, age was found to be a predictor. This is in agreement with a similar study by Guerra-Neira et al [ 25 ] who reported an inverse correlation between of age and multiplicity of Plasmodium infection, with children under five years of age having higher frequency of mixed Plasmodium malaria compared to individuals older than five years of age. Children younger than two years in our study were found to be less likely to have mixed malaria infections compared to those aged from two to five years.…”

Section: Discussionsupporting

confidence: 93%

“…Indeed, the dynamics of immunity in neonates, infants and toddlers is quite remarkable resulting in variable susceptibility to infection [ 27 , 28 ]. Noteworthy here is that, unlike the study by Guerra-Neira et al [ 25 ], our study population was limited to children younger than five years of age. In addition, these findings could be attributed to the use of insecticide-treated nets (ITNs) in that younger children tend to sleep under ITNs as breast-feeding infants but, at the age of two-to-three years, they are weaned off from breasting feeding and may not sleep under an ITN.…”

Section: Discussionmentioning

confidence: 99%

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Patterns of mixed Plasmodium species infections among children six years and under in selected malaria hyper-endemic communities of Zambia: population-based survey observations

et al. 2015

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BackgroundAlthough malaria is preventable and treatable, it still claims 660,000 lives every year globally with children under five years of age having the highest burden. In Zambia, malaria rapid diagnostic tests (RDTs) that only detect Plasmodium falciparum are the main confirmatory means for malaria diagnosis in most health facilities without microscopy services. As a consequence of this P. falciparum species diagnostic approach, non-falciparum malaria is not only under-diagnosed but entirely missed, thereby making the exact disease burden unknown. We thus investigated the prevalence of various Plasmodium spp. and associated burden of infection in selected communities in Zambia.MethodsData from two malaria hyper-endemic provinces (Eastern and Luapula) of the 2012 National Malaria Indicator Survey (MIS), conducted between April and May 2012, were used. The MIS is a nationally representative, two-stage cluster survey conducted to coincide with the end of the malaria transmission season. Social, behavioural and background information were collected from households as part of the survey. Thick blood smears, RDTs and dried blood spots (DBS) were collected from children below six years of age. Slides were stained using Giemsa and examined by microscopy while polymerase chain reaction (PCR) was used to analyse the DBS for malaria Plasmodium spp. Multivariate logistic regression was employed to examine the association between background factors and malaria.ResultsOverall, 873 children younger than six years of age were surveyed. The overall prevalence of Plasmodium spp. by PCR was 54.3% (95% CI 51–57.6%). Of the total Plasmodium isolates, 88% were P. falciparum, 10.6% were mixed infections and 1.4% were non-falciparum mono infections. Among the mixed infections, the majority were a combination of P. falciparum and P. malariae (6.5% of all mixed infections). Children two years and older (2–5 years) had three-fold higher risk of mixed malaria infections (aOR 2.8 CI 1.31–5.69) than children younger than two years of age.ConclusionThe high prevalence of mixed Plasmodium spp. infections in this population stresses review of the current malaria RDT diagnostic approaches. The observed less incidence of mixed infections in children under two years of age compared to their older two-to-five-year-old counterparts is probably due to the protective maternal passive immunity, among other factors, in that age group.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Patterns of mixed Plasmodium species infections among children six years and under in selected malaria hyper-endemic communities of Zambia: population-based survey observations

et al. 2015

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“…Malaria is endemic in Equatorial Guinea with stable transmission [ 1 ] and remains the major cause of morbidity and mortality among children under five years of age [ 2 ].…”

Section: Introductionmentioning

confidence: 99%

Rural-Urban Differences in Household Treatment-Seeking Behaviour for Suspected Malaria in Children at Bata District, Equatorial Guinea

et al. 2015

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BackgroundMalaria remains a major cause of morbidity and mortality among children under five years old in Equatorial Guinea. However, little is known about the community management of malaria and treatment-seeking patterns. We aimed to assess symptoms of children with reported malaria and treatment-seeking behaviour of their caretakers in rural and urban areas in the Bata District.MethodologyA cross-sectional study was conducted in the district of Bata and 440 houses were selected from 18 rural villages and 26 urban neighbourhoods. Differences between rural and urban caregivers and children with reported malaria were assessed through the chi-squared test for independence of categorical variables and the t-Student or the non-parametric Mann-Whitney test for normally or not-normally distributed continuous variables, respectively.ResultsDifferences between rural and urban households were observed in caregiver treatment-seeking patterns. Fever was the main symptom associated with malaria in both areas. Malaria was treated first at home, particularly in rural areas. The second step was to seek treatment outside the home, mainly at hospital and Health Centre for rural households and at hospital and private clinic for urban ones. Artemether monotherapy was the antimalarial treatment prescribed most often. Households waited for more than 24 hours before seeking treatment outside and delays were longest in rural areas. The total cost of treatment was higher in urban than in rural areas in Bata.ConclusionsThe delays in seeking treatment, the type of malaria therapy received and the cost of treatment are the principal problems found in Bata District. Important steps for reducing malaria morbidity and mortality in this area are to provide sufficient supplies of effective antimalarial drugs and to improve malaria treatment skills in households and in both public and private sectors.

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“…Some of the patient parameters investigated in our study had been previously reported to influence P . vivax infections [ 48 – 51 ]. For example, some hemoglobin variants [ 52 , 53 ] and G6PD genotypes [ 54 , 55 ] might confer some degree of protection against P .…”

Section: Discussionmentioning

confidence: 99%

Complexity of Infection and Genetic Diversity in Cambodian Plasmodium vivax

et al. 2016

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BackgroundPlasmodium vivax is the most widely distributed human malaria parasite with 2.9 billion people living in endemic areas. Despite intensive malaria control efforts, the proportion of cases attributed to P. vivax is increasing in many countries. Genetic analyses of the parasite population and its dynamics could provide an assessment of the efficacy of control efforts, but, unfortunately, these studies are limited in P. vivax by the lack of informative markers and high-throughput genotyping methods.Methodology/Principal FindingsWe developed a sequencing-based assay to simultaneously genotype more than 100 SNPs and applied this approach to ~500 P. vivax-infected individuals recruited across nine locations in Cambodia between 2004 and 2013. Our analyses showed that the vast majority of infections are polyclonal (92%) and that P. vivax displays high genetic diversity in Cambodia without apparent geographic stratification. Interestingly, our analyses also revealed that the proportion of monoclonal infections significantly increased between 2004 and 2013, possibly suggesting that malaria control strategies in Cambodia may be successfully affecting the parasite population.Conclusions/SignificanceOur findings demonstrate that this high-throughput genotyping assay is efficient in characterizing P. vivax diversity and can provide valuable insights to assess the efficacy of malaria elimination programs or to monitor the spread of specific parasites.

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Plasmodiumdiversity in non-malaria individuals from the Bioko Island in Equatorial Guinea (West Central-Africa)

Cited by 29 publications

References 10 publications

Patterns of mixed Plasmodium species infections among children six years and under in selected malaria hyper-endemic communities of Zambia: population-based survey observations

Patterns of mixed Plasmodium species infections among children six years and under in selected malaria hyper-endemic communities of Zambia: population-based survey observations

Rural-Urban Differences in Household Treatment-Seeking Behaviour for Suspected Malaria in Children at Bata District, Equatorial Guinea

Complexity of Infection and Genetic Diversity in Cambodian Plasmodium vivax

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