Transmission efficiency of Plasmodium vivax at low parasitaemia.

Background: Plasmodium vivax is responsible for much of malaria outside Africa. Although most P. vivax infections in endemic areas are asymptomatic and have low parasite densities, they are considered a potentially important source of transmission.

Controlled human malaria infection with a clone of Plasmodium vivax with high-quality genome assembly.

Controlled human malaria infection (CHMI) provides a highly informative means to investigate host-pathogen interactions and enable in vivo proof-of-concept efficacy testing of new drugs and vaccines. However, unlike Plasmodium falciparum, well-characterized P. vivax parasites that are safe and suitable for use in modern CHMI models are limited.

Sensitive detection of Plasmodium vivax malaria by the rotating-crystal magneto-optical method in Thailand.

The rotating-crystal magneto-optical detection (RMOD) method has been developed for the rapid and quantitative diagnosis of malaria and tested systematically on various malaria infection models. Very recently, an extended field trial in a high-transmission region of Papua New Guinea demonstrated its great potential for detecting malaria infections, in particular Plasmodium vivax. In the present small-scale field test, carried out in a low-transmission area of Thailand, RMOD confirmed malaria in all samples found to be infected with Plasmodium vivax by microscopy, our reference method.

Malaria cross-sectional surveys identified asymptomatic infections of Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi in Surat Thani, a southern province of Thailand.

Objectives: Malaria cross-sectional surveys are rarely conducted in very low transmission settings. This study aimed to determine the prevalence and risk factors of Plasmodium infection in a near-elimination setting in southern Thailand.

Methods: Two cross-sectional surveys were conducted in areas of active transmission in the Surat Thani province of Thailand in January and May 2019.

Comparison of PCR and microscopy for the detection of asymptomatic malaria in a Plasmodium falciparum/vivax endemic area in Thailand.

Objective: The main objective of this study was to compare the performance of nested PCR with expert microscopy as a means of detecting Plasmodium parasites during active malaria surveillance in western Thailand.

Methods: The study was performed from May 2000 to April 2002 in the village of Kong Mong Tha, located in western Thailand. Plasmodium vivax (PV) and Plasmodium falciparum (PF) are the predominant parasite species in this village, followed by Plasmodium malariae (PM) and Plasmodium ovale (PO).

Infectivity of asymptomatic Plasmodium-infected human populations to Anopheles dirus mosquitoes in western Thailand.

The infectivity of Plasmodium-infected humans in western Thailand was estimated by feeding laboratory-reared Anopheles dirus Peyton and Harrison mosquitoes on venous blood placed in a membrane-feeding apparatus. Between May 2000 and November 2001, a total of 6,494 blood films collected during an active malaria surveillance program were checked by microscopy for the presence of Plasmodium parasites: 3.3, 4.

Comparison of artificial membrane feeding with direct skin feeding to estimate the infectiousness of Plasmodium vivax gametocyte carriers to mosquitoes.

The efficacy of a membrane-feeding apparatus as a means of infecting Anopheles dirus mosquitoes with Plasmodium vivax was compared with direct feeding of mosquitoes on gametocyte carriers. Volunteers participating in the study were symptomatic patients reporting to malaria clinics in western Thailand. Direct mosquito feeds were conducted on 285 P.

Short report: Failure of the OptiMAL rapid malaria test as a tool for the detection of asymptomatic malaria in an area of Thailand endemic for Plasmodium falciparum and P. vivax.

We evaluated the efficacy of the OptiMAL assay in a cross-sectional malaria survey in western Thailand from April to August 2001. Expert microscopy of Giemsa-stained thick and thin blood films was used as the gold standard. Positive control lines were evident in 99% (1,128 of 1,137) of the assays tested.

Comparison of field and expert laboratory microscopy for active surveillance for asymptomatic Plasmodium falciparum and Plasmodium vivax in western Thailand.

Microscopy of Giemsa-stained thick and thin films by a skilled microscopist has remained the standard laboratory method for the diagnosis of malaria. However, diagnosis of malaria with this method is problematic since interpretation of results requires considerable expertise, particularly at low parasite levels. We compared the efficacy of "field" and "expert laboratory" microscopy for active surveillance of Plasmodium falciparum and P.

Field evaluation of the ICT Malaria Pf/Pv immunochromatographic test for the detection of asymptomatic malaria in a Plasmodium falciparum/vivax endemic area in Thailand.

Rapid antigen assays provide an effective tool for the detection of malaria in symptomatic patients. However, the efficacy of these devices for detecting asymptomatic malaria, where parasite levels are normally significantly lower than in symptomatic patients, is less well established. We evaluated the efficacy of a new combined Plasmodium falciparum-Plasmodim vivax immunochromatographic test (ICT Malaria Pf/Pv) in a cross-sectional malaria survey of the village of Ban Kong Mong Tha, Kanchanaburi Provice, Thailand, from August to December 2000.