Knowledge, attitudes, and practices (KAP) during the malaria elimination phase: A household-based cross-sectional survey.

Malaria is a major health problem in Southwestern Saudi Arabia. This study aimed to measure the level of community understanding of malaria transmission, protection, and treatment. A questionnaire-based cross-sectional study enrolled 1070 participants from 2 districts with different malaria prevalence rates in Jazan Province.

Variation of antibody responses to antigen with parasitaemia and polymorphism in Khartoum state, Sudan.

A hospital-based cross-sectional study was conducted at Khartoum state to investigate the variation of antibody responses to 19-kDa C-terminal region of merozoite surface protein 1 antigen and the variation of human polymorphism with parasitaemia. Measurements of natural acquisition of anti- IgG, IgG1 and IgG3 antibodies were performed using ELISA. Molecular characterization of polymorphism was achieved.

Adaptation of Plasmodium falciparum to its transmission environment.

Success in eliminating malaria will depend on whether parasite evolution outpaces control efforts. Here, we show that Plasmodium falciparum parasites (the deadliest of the species causing human malaria) found in low-transmission-intensity areas have evolved to invest more in transmission to new hosts (reproduction) and less in within-host replication (growth) than parasites found in high-transmission areas. At the cellular level, this adaptation manifests as increased production of reproductive forms (gametocytes) early in the infection at the expense of processes associated with multiplication inside red blood cells, especially membrane transport and protein trafficking.

Seroepidemiology of Toxoplasma gondii amongst Pregnant Women in Jazan Province, Saudi Arabia.

Background. Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite of worldwide distribution.

Immunological characteristics of hyperreactive malarial splenomegaly syndrome in sudanese patients.

Hyperreactive Malarial Splenomegaly (HMS) is defined as a massive enlargement of the spleen resulting from abnormal immune responses after repeated exposure to the malaria parasites. This study was carried out in Khartoum, Sudan. Sudan is considered to be one of the countries where HMS is quite prevalent.

Pattern of malaria transmission along the Rahad River basin, Eastern Sudan.

Background: Understanding malaria vector mosquitoes and their infectivity dynamics is of importance in setting up intervention and control programmes. Patterns of malaria transmission have been shown to differ between non-irrigated and irrigated semi-arid areas of eastern Sudan. However, very little information is available regarding malaria transmission dynamics along the seasonal river's basin.

The spatial-temporal clustering of Plasmodium falciparum infection over eleven years in Gezira State, The Sudan.

Background: Malaria infection and disease exhibit microgeographic heterogeneity which if predictable could have implications for designing small-area intervention. Here, the space-time clustering of Plasmodium falciparum infections using data from repeat cross-sectional surveys in Gezira State, a low transmission area in northern Sudan, is investigated.

Methods: Data from cross-sectional surveys undertaken in January each year from 1999-2009 in 88 villages in the Gezira state were assembled.

Loss of balancing selection in the betaS globin locus.

Background: Probably the best example of the rise and maintenance of balancing selection as an evolutionary trend is the role of S-haemoglobin (HbS - rs334) in protecting from malaria. Yet, the dynamics of such a process remains poorly understood, particularly in relation to different malaria transmission rates and the genetic background of the affected populations.

Methods: We investigated the association of haemoglobin HbS in protection from clinical episodes of malaria in two populations/villages where malaria is endemic, but mostly presenting in mild clinical forms.

Hyper-reactive Malarial Splenomegaly (HMS) in malaria endemic area in Eastern Sudan.

Hyper-reactive Malarial Splenomegaly (HMS) is massive enlargement of the spleen resulting from abnormal immune response to repeated attacks of malaria. The present study was carried out in Kassala city, Eastern Sudan where HMS is considered as highly prevalent. The objectives of this study were to determine the incidence of HMS in Eastern Sudan, and to identify basic laboratory and clinical characteristics of this condition in Sudanese patients.

In vivo switching between variant surface antigens in human Plasmodium falciparum infection.

A semi-immune individual was retrospectively found to have maintained an apparently monoclonal and genotypically stable asymptomatic infection for months after clinical cure of a Plasmodium falciparum malaria episode. Before the attack, the individual had no antibodies to variant surface antigens (VSAs) expressed by an isolate (isolate A) obtained at the time of the episode or by a genotypically identical isolate (isolate B) obtained from the same individual 3 months later. Six weeks after the attack, a strong isolate A-specific VSA antibody response had developed in the complete absence of isolate B-specific antibodies.