Under the current epidemiological conditions as found in Korea, and considering the limited funds available for the malaria project, passive case detection proved to be the only practical mechanism to obtain reliable data required for the delimitation of malarious areas. The malaria map of the country was completed at the end of 1965. The high SPRs found among the blood smears reported by the PCD undts are due to the fact that the Korean farmer is able to recognize the clinical symptoms of the disease. The "fever case" reports are therefore actually "suspect malaria case" reports. The consistently high SPR has resulted in the detection of a large number of parasite carriers with the number of smears to be examined being reduced to a minimum. Although the medical group gave an important contribution to the success of the PCD service in Korea, the number of medical and public health facilities in the rural areas are still too small. This made it necessary to obtain the collaboration of laymen groups like school teachers, village chiefs etc., and their participation largely contributed to the success of the present programme. The degree of collaboration by the PCD units is higher in the more malarious areas. As no form of encouragement e.g., a reporting fee, has been given to these laymen during the past few years it becomes increasingly more difficult to maintain their active co-operation. It is felt that through passive case detection alone it will not be possible to collect adequate information to provide the proof for the complete interruption of transmission.
parasitology-protozoa ; Plasmodium vivax ; malaria ; diagnosis ; epidemiology

Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/microL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/microL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Erythrocytes/parasitology ; Female ; Humans ; Malaria, Vivax/*diagnosis/epidemiology/parasitology ; Male ; Middle Aged ; Parasitemia/*diagnosis/epidemiology/parasitology ; Plasmodium vivax/isolation & purification ; Republic of Korea/epidemiology

Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/microL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/microL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Erythrocytes/parasitology ; Female ; Humans ; Malaria, Vivax/*diagnosis/epidemiology/parasitology ; Male ; Middle Aged ; Parasitemia/*diagnosis/epidemiology/parasitology ; Plasmodium vivax/isolation & purification ; Republic of Korea/epidemiology

Prevalence rates reported for malaria in pregnancy in Nigeria vary considerably. The accuracy of results of malaria diagnosis is dependent on training, experience, and motivation of the microscopist as well as the laboratory facility available. Results of training programmes on malaria microscopy have shown low levels of sensitivity and specificity of those involved in malaria diagnosis routinely and for research. This study was done to ascertain the true prevalence of malaria in pregnancy in Lagos, South-West Nigeria. A total of 1,084 pregnant women were recruited into this study. Blood smears stained with Giemsa were used for malaria diagnosis by light microscopy. Malaria infection during pregnancy presents mostly as asymptomatic infection. The prevalence of malaria in this population was 7.7% (95% confidence interval; 6.2-9.4%). Factors identified to increase the risk of malaria infection include young maternal age (< 20 years), and gravidity (primigravida). In conclusion, this study exposes the over-diagnosis of malaria in pregnancy and the need for training and retraining of laboratory staffs as well as establishing the malaria diagnosis quality assurance programme to ensure the accuracy of malaria microscopy results at all levels.
Adult ; Blood/parasitology ; Female ; Humans ; Malaria/diagnosis/*epidemiology ; Microscopy ; Nigeria/epidemiology ; Pregnancy ; Pregnancy Complications, Infectious/*epidemiology ; Pregnant Women ; Prevalence ; Young Adult

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

Prompt and accurate diagnosis of malaria is the key to prevent disease morbidity and mortality. This study was carried out to evaluate diagnostic performance of 3 commercial rapid detection tests (RDTs), i.e., Malaria Antigen Pf/Pantrade mark, Malaria Ag-Pftrade mark, and Malaria Ag-Pvtrade mark tests, in comparison with the microscopic and PCR methods. A total of 460 blood samples microscopically positive for Plasmodium falciparum (211 samples), P. vivax (218), mixed with P. falciparum and P. vivax (30), or P. ovale (1), and 124 samples of healthy subjects or patients with other fever-related infections, were collected. The sensitivities of Malaria Ag-Pftrade mark and Malaria Antigen Pf/Pantrade mark compared with the microscopic method for P. falciparum or P. vivax detection were 97.6% and 99.0%, or 98.6% and 99.0%, respectively. The specificities of Malaria Ag-Pftrade mark, Malaria Ag-Pvtrade mark, and Malaria Antigen Pf/Pantrade mark were 93.3%, 98.8%, and 94.4%, respectively. The sensitivities of Malaria Ag-Pftrade mark, Malaria Antigen Pf/Pantrade mark, and microscopic method, when PCR was used as a reference method for P. falciparum or P. vivax detection were 91.8%, 100%, and 96.7%, or 91.9%, 92.6%, and 97.3%, respectively. The specificities of Malaria Ag-Pftrade mark, Malaria Ag-Pvtrade mark, Malaria Antigen Pf/Pantrade mark, and microscopic method were 66.2%, 92.7%, 73.9%, and 78.2%, respectively. Results indicated that the diagnostic performances of all the commercial RDTs are satisfactory for application to malaria diagnosis.
Antigens, Protozoan/blood ; Cross-Sectional Studies ; *Diagnostic Techniques and Procedures/instrumentation ; Endemic Diseases/statistics & numerical data ; Humans ; Malaria/*diagnosis/epidemiology/parasitology ; Malaria, Vivax ; Plasmodium falciparum/genetics/immunology/*isolation & purification ; Reagent Kits, Diagnostic ; Thailand/epidemiology

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

An ELISA was developed for the diagnosis of vivax malaria using multiple stage-specific recombinant antigens of Plasmodium vivax. The DNA from the whole blood of a malaria patient was used as template to amplify the coding regions for the antigenic domains of circumsporozoite protein (CSP-1), merozoite surface protein (MSP-1), apical merozoite antigen (AMA-1), serine repeat antigen (SERA), and exported antigen (EXP-1). Each amplified DNA fragment was inserted into pQE30 plasmid to induce the expression of His-tagged protein in Escherichia coli (M15 strain) by IPTG. His-tagged proteins were purified by Ni-NTA metal-affinity chromatography and used as antigens for ELISA with patient sera that were confirmed previously by blood smear examinations. When applied to patient sera, 122 (80.3%) out of 152 vivax malaria cases reacted to at least one antigen, while no reactions were observed with 128 uninfected serum samples. We applied this ELISA to the screening of 3, 262 civilian residents in endemic regions near the DMZ, which resulted in 236 positively detected (7.2%) cases. This method can be applied to serological diagnosis and mass screening in endemic regions, or can be used as a safety test for transfusion blood in endemic areas.
Animals ; Antibodies, Protozoan/*blood ; Antigens, Protozoan/genetics/*immunology ; *Endemic Diseases ; Enzyme-Linked Immunosorbent Assay/methods ; Humans ; Life Cycle Stages ; Malaria, Vivax/*diagnosis/epidemiology/parasitology ; Mass Screening ; Plasmodium vivax/*growth & development/immunology ; Recombinant Proteins/*immunology ; Serologic Tests