Understanding genetic diversity in natural populations is a fundamental objective of evolutionary biology. The immune genes of the major histocompatibility complex (MHC) are excellent candidates to study such diversity because they are highly polymorphic in populations. Although balancing selection may be responsible for maintaining diversity at these functionally important loci, temporal varia...

The northern Andes, with their steep elevational and climate gradients, are home to an exceptional diversity of flora and fauna, particularly rich in avian species that have adapted to divergent ecological conditions. With this diversity comes the opportunity for parasites to exploit a wide breadth of avian hosts. However, little research has focused on examining the patterns of prevalence and ...

Malaria infections commonly contain multiple genetically distinct variants. Mathematical and animal models suggest that interactions among these variants have a profound impact on the emergence of drug resistance. However, methods currently used for quantifying parasite diversity in individual infections are insensitive to low-abundance variants and are not quantitative for variant population s...

Despite the ubiquity and ecological importance of parasites, relatively few studies have assessed their response to anthropogenic environmental change. Heuristic models have predicted both increases and decreases in parasite abundance in response to human disturbance, with empirical support for both. However, most studies focus on one or a few selected parasite species. Here, we assess the abun...

Coevolutionary interactions such as those between hosts and parasites have been regarded as an underlying cause of evolutionary diversification, but evidence from natural populations is limited. Among primates and other mammalian groups, measures of host diversification rates vary widely among lineages, but comparative studies have not yet identified a reliable explanation for this variation. I...

The drivers of regional parasite distributions are poorly understood, especially in comparison with those of free-living species. For vector-transmitted parasites, in particular, distributions might be influenced by host-switching and by parasite dispersal with primary hosts and vectors. We surveyed haemosporidian blood parasites (Plasmodium and Haemoproteus) of small land birds in eastern Nort...

Sex ratio theory posits that the adaptive proportion of male to female gametocytes of a malaria parasite within the vertebrate host depends on the degree of inbreeding within the vector. Gametocyte sex ratio could be phenotypically flexible, being altered based on the infection's clonal diversity, and thus likely inbreeding. This idea was tested by manipulating the clonal diversity of infection...

The tick-borne protozoan parasite Theileria parva causes East Coast fever (ECF), a severe lymphoproliferative disease of cattle that is a major constraint to the improvement of livestock in eastern, central and southern Africa. Studies in cattle experimentally infected with T. parva have shown that the protective cytotoxic T lymphocyte (CTL) response is tightly focused, with individual animals ...

Babesia bovis is a tick-transmitted haemoprotozoan and a causative agent of bovine babesiosis, a cattle disease that causes significant economic loss in tropical and subtropical regions. A panel of nineteen micro- and minisatellite markers was used to estimate population genetic parameters of eighteen parasite isolates originating from different continents, countries and geographic regions incl...