Those adults and children residing in selected survey households in the area of Ijara Town and its 5 km environs who are 1 year of age and older will be eligible, provided:
- Informed consent is obtained and signed, and assent form is obtained and signed from children age 7 and older,
- Subject has understanding of study procedures, and
- Subject is able to comply with study procedures for the entire length of the study.
- Age less than 1 year.
- Subjects who immigrated to the study area less than 2 years previously.
- Acutely ill Ijara residents.
- Adults and children who cannot provide informed consent or who cannot participate fully in the study procedures will also be excluded.