Detecting transmission areas of malaria parasites in a migratory bird species

Abstract

The identification of the regions where vector-borne diseases are transmitted is essential to study transmission patterns and to recognize future changes in environmental conditions that may potentially influence the transmission areas. SGS1, one of the lineages of Plasmodium relictum, is known to have active transmission in tropical Africa and temperate regions of Europe. Nuclear sequence data from isolates infected with SGS1 (based on merozoite surface protein 1 (MSP1) allelic diversity) have provided new insights on the distribution and transmission areas of these allelic variants. For example, MSP1 alleles transmitted in Africa differ from those transmitted in Europe, suggesting the existence of two populations of SGS1 lineages. However, no study has analysed the distribution of African and European transmitted alleles in Afro-Palearctic migratory birds. With this aim, we used a highly variable molecular marker to investigate whether juvenile house martins become infected in Europe before their first migration to Africa. We explored the MSP1 allelic diversity of P. relictum in adult and juvenile house martins. We found that juveniles were infected with SGS1 during their first weeks of life, confirming active transmission of SGS1 to house martins in Europe. Moreover, we found that all the juveniles and most of adults were infected with one European transmitted MSP1 allele, whereas two adult birds were infected with two African transmitted MSP1 alleles. These findings suggest that house martins are exposed to different strains of P. relictum in their winter and breeding quarters.

Migratory birds as vehicles for parasite dispersal? Infection by avian haemosporidians over the year and throughout the range of a long‐distance migrant

“…Therefore, the potential for haemosporidian dispersal by Grey‐cheeked Thrushes to bird assemblages outside its breeding areas is greatest during fall and spring migration and is more limited during wintering. Similar seasonal patterns of parasite prevalence have been documented in other migratory birds (García‐Longoria et al., ; Pérez‐Tris & Bensch, ; Sorensen et al., ).…”

“…We found evidence that juvenile Grey‐cheeked Thrushes carry haemosporidian parasites during their first fall migration, indicating a potential role of young birds as vehicles for parasite dispersal from temperate to tropical areas (García‐Longoria et al., ; Waldenström et al., ). However, none of the lineages infecting juvenile Grey‐cheeked Thrushes in the fall have been found in tropical resident birds and juveniles did not appear to become infected with tropical parasite lineages before spring migration, suggesting that the role of young birds in moving parasites between regions is limited and not different from that of adult birds.…”

“…However, none of the lineages infecting juvenile Grey‐cheeked Thrushes in the fall have been found in tropical resident birds and juveniles did not appear to become infected with tropical parasite lineages before spring migration, suggesting that the role of young birds in moving parasites between regions is limited and not different from that of adult birds. Our data on the distribution of lineages across periods in juvenile birds indicate that transmission is likely occurring mostly on the breeding grounds (García‐Longoria et al., ; Sorensen et al., ), where the most prevalent lineages infecting Grey‐cheeked Thrush are shared with other species of boreal birds (Dodge et al., ; Loiseau et al., ; Oakgrove et al., ).…”

“…Because of their immunological naiveté, juvenile birds are expected to be especially susceptible to infection on the breeding grounds and may thus be important vehicles for long‐distance parasite dispersal to wintering areas during their first migration. Juveniles may also be likely to become infected with parasites while migrating or wintering and to subsequently disperse parasites to breeding areas upon their return (García‐Longoria et al., ; Hammers et al., ; Marzal et al., ; Valkiūnas, ). However, little is known about the role of juvenile birds versus adults as vehicles for parasites over long distances (Gutiérrez‐López et al., ) because information on the prevalence, transmission, and diversity of lineages carried by birds of different ages during migration and stationary nonbreeding periods is limited (Bensch & Akesson, ; Dodge et al., ; Hasselquist et al., ; Valkiūnas, ; Waldenström et al., ).…”

Importance of infection of haemosporidia blood parasites during different life history stages for long‐term reproductive fitness of collared flycatchers

“…Given the above mentioned vulnerabilities of young animals to parasite infection; infancy in vertebrates is potentially a stage of the life cycle with a high rate of parasite transmission. Moreover, in a recent study, juvenile house martins were found to be exposed to the haemosporidia parasite, Plasmodium relictum (PSGS1), supporting the idea that early-life conditions are important in the interaction between haemosporidia parasites and avian hosts (Garcia-Longoria et al 2015). Indeed, hosts infected by haemosporidia blood parasites during reproduction are likely to be chronically infected, since the initial acute phase of infection is detrimental to the hosts health (Atkinson and Van Riper III 1991, Atkinson et al 2001, Zuk and Stoehr 2002, leading to the abandonment of energetically costly behaviours, such as reproduction, in favour of recovery (Wingfield et al 1998).…”