Avian influenza surveillance in Central and West Africa, 2010-2014.

Avian influenza virus (AIV) is an important zoonotic pathogen, resulting in global human morbidity and mortality and substantial economic losses to the poultry industry. Poultry and wild birds have transmitted AIV to humans, most frequently subtypes H5 and H7, but also different strains and subtypes of H6, H9, and H10. Determining which birds are AIV reservoirs can help identify human populations that have a high risk of infection with these viruses due to occupational or recreational exposure to the reservoir species. To assess the prevalence of AIV in tropical birds, from 2010 to 2014, we sampled 40 099 birds at 32 sites in Central Africa (Cameroon, Central African Republic, Congo-Brazzaville, Gabon) and West Africa (Benin, Côte d'Ivoire, Togo). In Central Africa, detection rates by real-time RT-PCR were 16·6% in songbirds (eight passerine families, n = 1257), 16·4% in kingfishers (family Alcedinidae, n = 73), 8·2% in ducks (family Anatidae, n = 564), and 3·65% in chickens (family Phasianidae, n = 1042). Public health authorities should educate human cohorts that have high exposure to these bird populations about AIV and assess their adherence to biosecurity practices, including Cameroonian farmers who raise small backyard flocks.

Detection and molecular characterization of avian Plasmodium from mosquitoes in central Turkey.

Assessing vector-parasite relationship is important in understanding the emergence of vector-borne diseases and the evolution of parasite diversity. This study investigates avian Plasmodium parasites in mosquitoes collected from Kayseri province in Central Anatolian, Turkey and determines the haemosporidian parasite lineages from these mosquito species. A total of 6153 female mosquitos from 6 species were collected from 46 sites during June-August of 2008 and 2009. Each mosquito's head-thorax and abdomen were separated, categorized with respect to species and collection area and pooled for DNA extraction. A total of 1198 genomic DNA pools (599 thorax-head, 599 abdomen) were constituted of which 128 pools (59 thorax-head, 69 abdomen) were positive for avian haemosporidian parasites (Plasmodium and Haemoproteus) by Nested-PCR analysis. Culex pipens, Aedes vexans, Culex theileri and Culiseta annulata were positive with minimum infection rates (MIRs) of 16.22 and 18.15, 4.72 and 5.98, 5.18 and 10.36, 10.64 and 10.64 in their thorax-head and abdomen parts, respectively. No avian haemosporidian DNA was detected from Culex hortensis and Anopheles maculipennis. Phylogenetic analyses of the partial cytb gene of avian haemosporidian mt-DNA from 13 positive pools revealed that 11 lineages in four phylogenic groups were Plasmodium and the other two were Haemoproteus. Our results suggest that Cx. pipiens could probably be the major vector of avian Plasmodium in Central Turkey. This is the first report of molecular detection and characterization of avian Plasmodium lineages from mosquitoes in Turkey.

Nonspecific patterns of vector, host and avian malaria parasite associations in a central African rainforest.

Malaria parasites use vertebrate hosts for asexual multiplication and Culicidae mosquitoes for sexual and asexual development, yet the literature on avian malaria remains biased towards examining the asexual stages of the life cycle in birds. To fully understand parasite evolution and mechanism of malaria transmission, knowledge of all three components of the vector-host-parasite system is essential. Little is known about avian parasite-vector associations in African rainforests where numerous species of birds are infected with avian haemosporidians of the genera Plasmodium and Haemoproteus. Here we applied high resolution melt qPCR-based techniques and nested PCR to examine the occurrence and diversity of mitochondrial cytochrome b gene sequences of haemosporidian parasites in wild-caught mosquitoes sampled across 12 sites in Cameroon. In all, 3134 mosquitoes representing 27 species were screened. Mosquitoes belonging to four genera (Aedes, Coquillettidia, Culex and Mansonia) were infected with twenty-two parasite lineages (18 Plasmodium spp. and 4 Haemoproteus spp.). Presence of Plasmodium sporozoites in salivary glands of Coquillettidia aurites further established these mosquitoes as likely vectors. Occurrence of parasite lineages differed significantly among genera, as well as their probability of being infected with malaria across species and sites. Approximately one-third of these lineages were previously detected in other avian host species from the region, indicating that vertebrate host sharing is a common feature and that avian Plasmodium spp. vector breadth does not always accompany vertebrate-host breadth. This study suggests extensive invertebrate host shifts in mosquito-parasite interactions and that avian Plasmodium species are most likely not tightly coevolved with vector species.