Armillifer-Infected Snakes Sold at Congolese Bushmeat Markets Represent an Emerging Zoonotic Threat

African pythons (Pythonidae) and large vipers (Bitis spp.) act as definitive hosts for Armillifer armillatus and Armillifer grandis parasites (Crustacea: Pentastomida) in the Congo Basin. Since the proportion of snakes in bushmeat gradually increases, human pentastomiasis is an emerging zoonotic disease. To substantiate the significance of this threat, we surveyed snakes offered for human consumption at bushmeat markets in the Kole district, Democratic Republic of the Congo, for the presence of adult pentastomids. In Bitis vipers (n = 40), Armillifer spp. infestations exhibited an 87.5% prevalence and 6.0 median intensity. Parasite abundance covaried positively with viper length, but not with body mass. In pythons (n = 13), Armillifer spp. exhibited a 92.3% prevalence and 3.5 median intensity. The positive correlations between parasite abundance and python length or mass were statistically nonsignificant. Ninety-one percent of A. grandis were discovered in vipers and 97% of infected vipers hosted A. grandis, whereas 81% of A. armillatus specimens were found in pythons and 63% of infected pythons hosted A. armillatus. Thus, challenging the widespread notion of strict host specificity, we found 'reversed' infections and even a case of coinfection. In this study, we also gathered information about the snake consumption habits of different tribal cultures in the area. Infective parasite ova likely transmit to humans directly by consumption of uncooked meat, or indirectly through contaminated hands, kitchen tools or washing water.

Primary analysis of the expressed sequence tags in a pentastomid nymph cDNA library

Background

Pentastomiasis is a rare zoonotic disease caused by pentastomids. Despite their worm-like appearance, they are commonly placed into a separate sub-class of the subphylum Crustacea, phylum Arthropoda. However, until now, the systematic classification of the pentastomids and the diagnosis of pentastomiasis are immature, and genetic information about pentastomid nylum is almost nonexistent. The objective of this study was to obtain information on pentastomid nymph genes and identify the gene homologues related to host-parasite interactions or stage-specific antigens.

Methodology/Principal Findings

Total pentastomid nymph RNA was used to construct a cDNA library and 500 colonies were sequenced. Analysis shows one hundred and ninety-seven unigenes were identified. In which, 147 genes were annotated, and 75 unigenes (53.19%) were mapped to 82 KEGG pathways, including 29 metabolism pathways, 29 genetic information processing pathways, 4 environmental information processing pathways, 7 cell motility pathways and 5 organismal systems pathways. Additionally, two host-parasite interaction-related gene homologues, a putative Kunitz inhibitor and a putative cysteine protease.

Conclusion/Significance

We first successfully constructed a cDNA library and gained a number of expressed sequence tags (EST) from pentastomid nymphs, which will lay the foundation for the further study on pentastomids and pentastomiasis.