The online version of this article (doi:10.1186/1475-2875-11-126) contains supplementary material, which is available to authorized users.
The authors declare that they have no competing interests.
SZ, AR and AAH designed the study. SZ developed the experimental protocols, supervised field and laboratory works, finalized the interpretation of the data and wrote down the manuscript. AR and AAH have also contributed to the analysis of the data and critically reading the content of the manuscript. SZ and AAM performed most of the laboratory work and also helped in analysing the data. HT helped partially in some of the laboratory work and also sampling in Bashagard district. RS and AA were also involved in field works and sampling in Bashagard and Ghale-Ganj districts, respectively. All authors read and approved the final manuscript.
In malaria endemic areas, continuous exposure to Plasmodium parasites leads to asymptomatic carriers that provide a fundamental reservoir of parasites, contributing to the persistence of malaria transmission. Therefore, in the present investigation, the presence and prevalence of malaria asymptomatic cases were determined to evaluate the reservoir of infection in two malaria endemic areas with a previous history of malaria transmission in the south of Iran, Bashagard and Ghale-Ganj districts of Hormozgan and Kerman provinces, respectively, where malaria transmission has been drastically reduced in the recent years.
The population samples (n=500 from each of the studied areas) were randomly collected from non-febrile, long-term residing, aged two to over 60years, during 20092010. Three identical surveys were carried out in both study areas and in each phase all the consent participants were interviewed and clinically examined. In all, three surveys to detect hidden parasite reservoirs (both Plasmodium falciparum and Plasmodium vivax), thick and thin blood smears and a highly sensitive nested-PCR were applied. In addition, the sero-prevalence survey for detecting malaria exposure was done by using a serological marker.
In this study, P. vivax and P. falciparum parasites were not detected by light microscopy and nested-PCR assay in all three surveys of samples. Antibody responses against P. vivax and P. falciparum were detected in 1 % and 0.2 % of the total examined individuals, respectively, in Bashagard district. Regarding to Ghale-Ganj district, about 0.9% of the individuals had IgG -specific antibody to P. vivax at the first and second surveys, but at the third survey 0.45% of the participants had positive antibody to P. vivax parasite. IgG -specific antibody to P. falciparum was detected in 0.2% of the participants at the first and follow-up surveys. The overall regional differences were not statistically significant (P>0.05).
Taken together, the lack of asymptomatic carrier with the evidence of extremely low sero-positive to both P. vivax and P. falciparum among examined individuals supported the limited recent transmission in the studied areas and, therefore, these parts of Iran have potential to eliminate the disease in the next few years. However, continued follow up and action are still needed in both studied areas and also in their neighbouring province, Sistan and Baluchistan, which has the highest reported cases of malaria in Iran and also, has the largest border line with Afghanistan and Pakistan, with no elimination activities. This data will provide useful information for managing elimination activities in Iran.
Authors’ original file for figure 112936_2012_2196_MOESM1_ESM.pdf
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- Survey for asymptomatic malaria cases in low transmission settings of Iran under elimination programme
Akram A Mehrizi
Ali A Haghdoost
Asadallah Ahmadi Kahanali
- BioMed Central
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