A new pathogen spillover from domestic to wild animals: Plasmodium juxtanucleare infects free-living passerines in Brazil

Abstract

Habitat modification may facilitate the emergence of novel pathogens, and the expansion of agricultural frontiers make domestic animals important sources of pathogen spillover to wild animals. We demonstrate for the first time that Plasmodium juxtanucleare, a widespread parasite from domestic chickens, naturally infects free-living passerines. We sampled 68 wild birds within and at the border of conservation units in central Brazil composed by Cerrado, a highly threatened biome. Seven out of 10 passerines captured in the limits of a protected area with a small farm were infected by P. juxtanucleare as was confirmed by sequencing a fragment of the parasite's cytochrome b. Blood smears from these positive passerines presented trophozoites, meronts and gametocytes compatible with P. juxtanucleare, meaning these birds are competent hosts for this parasite. After these intriguing results, we sampled 30 backyard chickens managed at the area where P. juxtanucleare-infected passerines were captured, revealing one chicken infected by the same parasite lineage. We sequenced the almost complete mitochondrial genome from all positive passerines, revealing that Brazilian and Asian parasites are closely related. P. juxtanucleare can be lethal to non-domestic hosts under captive and rehabilitation conditions, suggesting that this novel spillover may pose a real threat to wild birds.

Molecular survey on the occurrence of avian haemosporidia, Coxiella burnetii and Francisella tularensis in waterfowl from central Italy

“…Haemosporidians occur worldwide except in Antarctica (Beadell et al, 2009) and most infections are relatively benign, probably due to long-term host parasites evolutionary associations (Bennet et al, 1993). The occurrence of these protozoa has been reported from several birds’ species (Schmid et al, 2017; Dimitrov et al, 2018; Ferreira-Junior et al, 2018; Valkiunas et al, 2019; Schumm et al, 2019) and from dipteran species (Ionică et al, 2017; Žiegytė et al, 2017; Martin et al, 2019; Schoener et al, 2019).…”

A novel group of avian astroviruses from Neotropical passerine birds broaden the diversity and host range of Astroviridae

“…Conversely, the valuable biodiversity of these regions may be threatened by invasive viruses imported into the Neotropics 7,8 . There is growing evidence that the risk of pathogen transfer is increasing in both directions 9–11 , and a comprehensive characterization of the virome of the local fauna may be instrumental in preventing any harmful impact. However, this important knowledge would hardly become available without exploratory approaches, which address the discovery and describe the diversity of viruses that affect non-model host species.…”

A Review of Pathogen Transmission at the Backyard Chicken–Wild Bird Interface

“…Pathogen transmission dynamics at the poultry-free-living bird interface are not only subject to within-host ecological and evolutionary pressures (138) but also, most importantly, are frequently bidirectional in nature (27,139,140). The establishment of "open-air" or "free-range" poultry habitats that overlap with wild bird habitats is a key step in the loss of sympatric species contact barriers, which may facilitate the transmission of opportunistic microbes (132,(141)(142)(143). The introduction of high densities of poultry into a diverse, susceptible avian community is likely to accelerate wild and domestic bird encounter rates with generalist pathogens.…”

“…These remaining studies provided evidence of pathogen spillover to and from domestic chickens and wild birds using genomic comparisons and molecular epidemiology techniques. Economically significant viruses such as HPAIV and NDV were highly represented (50, 139,141,146,158,190,[235][236][237], whereas bacterial and parasitic species were less so (141,162,180). A contributing factor to this scarcity of evidence is likely that the mechanisms of transmission differ across pathogens and avian host species (238,239).…”