Merozoite surface proteins (MSPs) of malaria parasites play critical roles during the erythrocyte invasion and so are potential candidates for malaria vaccine development. However, because MSPs are often under strong immune selection, they can exhibit extensive genetic diversity. The gene encoding the merozoite surface protein-3 (MSP-3) of Plasmodium falciparum displays 2 allelic types, K1 and 3D7. In Thailand, the allelic frequency of the P. falciparum msp-3 gene was evaluated in a single P. falciparum population in Tak at the Thailand and Myanmar border. However, no study has yet looked at the extent of genetic diversity of the msp-3 gene in P. falciparum populations in other localities. Here, we genotyped the msp-3 alleles of 63 P. falciparum samples collected from 5 geographical populations along the borders of Thailand with 3 neighboring countries (Myanmar, Laos, and Cambodia). Our study indicated that the K1 and 3D7 alleles coexisted, but at different proportions in different Thai P. falciparum populations. K1 was more prevalent in populations at the Thailand-Myanmar and Thailand-Cambodia borders, whilst 3D7 was more prevalent at the Thailand-Laos border. Global analysis of the msp-3 allele frequencies revealed that proportions of K1 and 3D7 alleles of msp-3 also varied in different continents, suggesting the divergence of malaria parasite populations. In conclusion, the variation in the msp-3 allelic patterns of P. falciparum in Thailand provides fundamental knowledge for inferring the P. falciparum population structure and for the best design of msp-3 based malaria vaccines.
Antigens, Protozoan/*genetics ; *Gene Frequency ; *Genetic Variation ; Genotype ; Humans ; Malaria, Falciparum/epidemiology/*parasitology ; Plasmodium falciparum/classification/*genetics/isolation & purification ; Polymorphism, Genetic ; Protozoan Proteins/*genetics ; Thailand/epidemiology

The relationship between anti-Plasmodium vivax circumsporozoite protein (CSP) antibody levels and the prevalence of malaria in epidemic areas of South Korea was evaluated. Blood samples were collected from inhabitants of Gimpo-si (city), Paju-si, and Yeoncheon-gun (county) in Gyeonggi-do (province), as well as Cheorwon-gun in Gangwon-do from November to December 2004. Microscopic examinations were used to identify malaria parasites. ELISA was used to quantitate anti-circumsporozoite protein (CSP) antibodies against P. vivax. A total of 1,774 blood samples were collected. The overall CSP-ELISA-positive rate was 7.7% (n=139). The annual parasite incidences (APIs) in these areas gradually decreased from 2004 to 2005 (1.09 and 0.80, respectively). The positive rate in Gimpo (10.4%, 44/425) was the highest identified by CSP-ELISA. The highest API was found in Yeoncheon, followed by Cheorwon, Paju, and Gimpo in both years. The positive rates of CSP-ELISA were closely related to the APIs in the study areas. These results suggest that seroepidemiological studies based on CSP may be helpful in estimating the malaria prevalence in certain areas. In addition, this assay can be used to establish and evaluate malaria control and eradication programs in affected areas.
Adolescent ; Adult ; Antibodies, Protozoan/*blood ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Incidence ; Malaria, Vivax/*blood/*epidemiology/parasitology ; Male ; Middle Aged ; Plasmodium vivax/*immunology/physiology ; Prevalence ; Protozoan Proteins/immunology ; Republic of Korea/epidemiology ; Seroepidemiologic Studies ; Young Adult

Hemoglobinopathy and malaria are commonly found worldwide particularly in malaria endemic areas. Thalassemia, the alteration of globin chain synthesis, has been reported to confer resistance against malaria. The prevalence of thalassemia was investigated in 101 malaria patients with Plasmodium falciparum and Plasmodium vivax along the Thai-Myanmar border to examine protective effect of thalassemia against severe malaria. Hemoglobin typing was performed using low pressure liquid chromatography (LPLC) and alpha-thalassemia was confirmed by multiplex PCR. Five types of thalassemia were observed in malaria patients. The 2 major types of thalassemia were Hb E (18.8%) and alpha-thalassemia-2 (11.9%). There was no association between thalassemia hemoglobinopathy and malaria parasitemia, an indicator of malaria disease severity. Thalassemia had no significant association with P. vivax infection, but the parasitemia in patients with coexistence of P. vivax and thalassemia was about 2-3 times lower than those with coexistence of P. falciparum and thalassemia and malaria without thalassemia. Furthermore, the parasitemia of P. vivax in patients with coexistence of Hb E showed lower value than coexistence with other types of thalassemia and malaria without coexistence. Parasitemia, hemoglobin, and hematocrit values in patients with coexistence of thalassemia other than Hb E were significantly lower than those without coexistence of thalassemia. Furthermore, parasitemia with coexistence of Hb E were 2 times lower than those with coexistence of thalassemia other than Hb E. In conclusion, the results may, at least in part, support the protective effect of thalassemia on the development of hyperparasitemia and severe anemia in malaria patients.
Female ; Hemoglobins/genetics/metabolism ; Humans ; Malaria, Falciparum/blood/complications/*genetics/parasitology ; Malaria, Vivax/blood/complications/*genetics/parasitology ; Male ; Middle Aged ; Plasmodium falciparum/physiology ; Plasmodium vivax/physiology ; Thailand/epidemiology ; Thalassemia/blood/complications/epidemiology/*genetics

To prevent and control infectious diseases was one of the major concerns of U.S. military government when they stationed in Korea in 1945. It was because the spread of various infectious diseases can cause social unrest and they can also affect the U.S. military. Malaria was one of the most important infectious diseases to which the U.S. military had been paying special attention. The U.S. military received a severe damage during the Pacific war with Japan due to malaria. It was said that more soldiers were lost by malaria than by battle itself. The bitter experience they had during the war made them accumulate more systematic and practical knowledge against malaria. As a result, by the end of the war, the U.S. military could run more than hundreds of units specialized in controlling malaria. Thanks to such a preparation, they could immediately begin their anti-malaria activities in Korea soon after the World War II. Although the vivax malaria, which is the dominant type in Korea, is not as much a fatal type as that in the Pacific areas, it was damaging enough to the infected. The 207th Malaria Survey Detachment carried out collecting and identifying the kinds of mosquitos in Korea. In addition, they also surveyed the prevalence of malaria among school children in Seoul. In terms of controlling malaria, DDT played a decisive role. Vector control is the most effective and ideal measurements against malaria. Before the development of DDT, it was practically impossible to eradicate mosquitos which arise from extremely broad areas. However, DDT could not be used as it had been expected in the rural area, because spraying DDT in the rice paddies which is the breeding place of mosquitos kills rice. Despite such a limitation in anti-malaria activities of the US military government, it should be noted that a significant turn in controlling malaria was possible thanks to the development of DDT.
History, 20th Century ; Humans ; Malaria/epidemiology/*history/parasitology/prevention & control ; Military Medicine/*history ; Military Personnel ; Republic of Korea/epidemiology ; United States

Malaria is a tropical disease caused by protozoans of the Plasmodium genus. Delayed diagnosis and misdiagnosis are strongly associated with higher mortality. In recent years, a greater importance is attributed to Plasmodium knowlesi, a species found mainly in Southeast Asia. Routine parasitological diagnostics are associated with certain limitations and difficulties in unambiguous determination of the parasite species based only on microscopic image. Recently, molecular techniques have been increasingly used for predictive diagnosis. The aim of the study is to draw attention to the risk of travelling to knowlesi malaria endemic areas and to raise awareness among personnel involved in the therapeutic process.
Asia, Southeastern ; Global Health ; Humans ; Malaria/diagnosis/*epidemiology/*parasitology ; Microscopy/methods ; Molecular Diagnostic Techniques/methods ; Plasmodium knowlesi/*isolation & purification ; Public Health

In order to determine the status of malaria among schoolchildren on Kome Island (Lake Victoria), near Mwanza, Tanzania, a total of 244 schoolchildren in 10 primary schools were subjected to a blood survey using the fingerprick method. The subjected schoolchildren were 123 boys and 121 girls who were 6-8 years of age. Only 1 blood smear was prepared for each child. The overall prevalence of malaria was 38.1% (93 positives), and sex difference was not remarkable. However, the positive rate was the highest in Izindabo Primary School (51.4%) followed by Isenyi Primary School (48.3%) and Bugoro Primary School (46.7%). The lowest prevalence was found in Muungano Primary School (16.7%) and Nyamiswi Primary School (16.7%). These differences were highly correlated with the location of the school on the Island; those located in the peripheral area revealed higher prevalences while those located in the central area showed lower prevalences. Plasmodium falciparum was the predominant species (38.1%; 93/244), with a small proportion of them mixed-infected with Plasmodium vivax (1.6%; 4/244). The results revealed that malaria is highly prevalent among primary schoolchildren on Kome Island, Tanzania, and there is an urgent need to control malaria in this area.
Blood/parasitology ; Child ; Coinfection/epidemiology/parasitology ; Cross-Sectional Studies ; Female ; Humans ; Malaria/*epidemiology/parasitology ; Male ; Microscopy ; Plasmodium falciparum/*isolation & purification ; Plasmodium vivax/*isolation & purification ; Prevalence ; Tanzania/epidemiology ; Topography, Medical

Congenital malaria is assumed to be a risk factor for infant morbidity and mortality in endemic areas like Maumere, Indonesia. Infected infants are susceptible to its impact such as premature labor, low birth weight, anemia, and other unspecified symptoms. The aim of this study was to investigate the prevalence of congenital malaria and the influence of mother-infant paired parasite densities on the clinical outcome of the newborns at TC Hillers Hospital, Maumere. An analytical cross sectional study was carried out in newborns which showed criteria associated with congenital malaria. A thick and thin blood smear confirmed by nested PCR was performed in both mothers and infants. The association of congenital malaria with the newborn's health status was then assessed. From 112 mother-infant pairs included in this study, 92 were evaluated further. Thirty-nine infants (42.4%) were found to be infected and half of them were asymptomatic. Infected newborns had a 4.7 times higher risk in developing anemia compared to uninfected newborns (95% CI, 1.3-17.1). The hemoglobin level, erythrocyte amount, and hematocrit level were affected by the infants' parasite densities (P<0.05). Focusing on newborns at risk of congenital malaria, the prevalence is almost 3 times higher than in an unselected collective. Low birth weight, anemia, and pre-term birth were the most common features. Anemia seems to be significantly influenced by infant parasite densities but not by maternal parasitemia.
Anemia/*etiology ; Blood/parasitology ; Cross-Sectional Studies ; Female ; Humans ; Indonesia/epidemiology ; *Infant, Low Birth Weight ; Infant, Newborn ; Malaria/*congenital/*epidemiology/pathology ; Male ; Microscopy ; Polymerase Chain Reaction ; Prevalence

The vir genes are antigenic genes and are considered to be possible vaccine targets. Since India is highly endemic to Plasmodium vivax, we sequenced 5 different vir genes and investigated DNA sequence variations in 93 single-clonal P. vivax isolates. High variability was observed in all the 5 vir genes; the vir 1/9 gene was highly diverged across Indian populations. The patterns of genetic diversity do not follow geographical locations, as geographically distant populations were found to be genetically similar. The results in general present complex genetic diversity patterns in India, requiring further in-depth population genetic and functional studies.
Antigens, Protozoan/*genetics ; Humans ; India/epidemiology ; Malaria, Vivax/epidemiology/parasitology ; Phylogeny ; Plasmodium vivax/*genetics ; *Polymorphism, Genetic ; Protozoan Proteins/genetics/*metabolism

Malaria is endemic across lowland Papua New Guinea (PNG) and case management has been based on symptomatic diagnosis and presumptive treatment of fever cases with an antimalarial. This study aimed to investigate the prevalence of malaria infection among fever cases presenting to 5 purposely selected sentinel health facilities in order to estimate the proportion of patients requiring antimalarial drugs. A total of 1807 fever patients were screened. Overall, 45% of fever patients had a positive malaria blood slide; 35% were infected with Plasmodium falciparum, 9% with P. vivax and 2% with P. malariae. Slide positivity was highest in Dreikikir (75%) and lowest in Wipim (2%). Among patients aged 1-4 years, 22% had moderate to severe anaemia (Hb < 8 g/dI) and 21% of children 2-9 years of age showed signs of splenomegaly (Hackett score 1-5). Comorbidity differed significantly between study sites and was not closely correlated with malaria infection. Clinical diagnosis by health facility staff was malaria for 67% of all fever cases, including 89% of slide-positive and 48% of slide-negative patients. 70% of rapid diagnostic test-negative cases were treated with an antimalarial. It is estimated that due to the lack of parasitological diagnosis the selected health facilities reported an excess of 18% (Dreikikir) to 98% (Wipim) malaria patients on average each month. In consideration of the significant differences in malaria-attributable fevers between study sites, the implementation of parasitological diagnosis in health facilities and administration of antimalarials only to test-positive patients has the potential to significantly improve the management of fever cases and reporting of malaria. A better tailoring to different settings may increase the effectiveness of malaria control interventions.
Adolescent ; Adult ; Child ; Child, Preschool ; Female ; Fever/*parasitology ; Humans ; Infant ; Malaria/complications/diagnosis/*epidemiology ; Male ; Papua New Guinea/epidemiology ; Young Adult

OBJECTIVETo determin the extent to which parvovirus B19 (B19V) and co-infection of B19V and malaria contribute to risk of anaemia in children.

METHODSB19V DNA and malaria parasites were screened for 234 children at the PML Children's Hospital in Accra. The role of B19V and co-infection with B19V and malaria in anaemia was evaluated by analysing full blood cell counts, malaria and B19V DNA results from these children.

RESULTSThe prevalence of B19V, malaria and co-infection with B19V and malaria was 4.7%, 41.9% and 2.6%, respectively. Malaria posed a greater risk in the development of mild anaemia compared to severe anaemia (OR=5.28 vrs 3.15) whereas B19V posed a higher risk in the development of severe anaemia compared to mild anaemia (OR=4.07 vrs 1.00) from a non-anaemic child. Persons with co-infection with B19V and malaria had 2.23 times the risk (95% CI=0.40-12.54) of developing severe anaemia should they already have a mild anaemia. The degree of anaemia was about three times affected by co-infection (Pillai's trace=0.551, P=0.001) as was affected by malaria alone (Pillai's trace=0.185, P=0.001). B19V alone did not significantly affect the development of anaemia in a non-anaemic child. Microcytic anaemia was associated with B19V and co-infection with B19V and malaria more than normocytic normochromic anaemia.

CONCLUSIONSB19V was associated with malaria in cases of severe anaemia. The association posed a significant risk for exacerbation of anaemia in mild anaemic children. B19V and co-infection with B19V and malaria may be associated with microcytic anaemia rather than normocytic normochromic anaemia as seen in cases of B19V infection among persons with red cell abnormalities.

Adolescent ; Anemia ; epidemiology ; etiology ; parasitology ; virology ; Child ; Child, Preschool ; Coinfection ; complications ; epidemiology ; parasitology ; physiopathology ; virology ; Female ; Ghana ; epidemiology ; Humans ; Infant ; Malaria, Falciparum ; complications ; epidemiology ; physiopathology ; Male ; Parvoviridae Infections ; complications ; epidemiology ; physiopathology ; Parvovirus B19, Human ; isolation & purification ; physiology ; Plasmodium falciparum ; isolation & purification ; physiology ; Polymerase Chain Reaction ; Prevalence ; Risk Factors