Asian snake farms: conservation curse or sustainable enterprise?

An outbreak of Providencia rettgeri bacteremia at a Ptyas mucosus farm in Hainan, China

Aim

To describe the histopathology and etiology of an outbreak of respiratory disease at a Ptyas mucosus farm in Hainan, China.

Methods and results

The etiology was confirmed by gross examination and microscopic analysis. The bacterial isolates from blood and internal organs were identified by biochemical analysis and 16S rRNA gene sequencing. The virulence and antibiotic resistance characteristics of the isolates were further demonstrated by polymerase chain reaction (PCR), disk diffusion testing, and LD50 analysis in Kunming mice. Histopathological analysis of the diseased P. mucosus revealed systemic lesions, including severe airway obstruction with large numbers of inflammatory cells and cellulose exudates in the lungs; severe multifocal hepatocyte vacuolar degeneration and necrosis in the liver with excessive inflammatory exudates and chronic granuloma; splenic hemorrhage and partial loss of splenic structure; and renal vascular and interstitial congestion. Providencia rettgeri was isolated from the blood and multiple internal organs (liver, spleen, kidneys, and lungs). All examined isolates (H1, H4, and H13) were multidrug-resistant but sensitive to four antibiotics-cefepime, imipenem, chloramphenicol, and ciprofloxacin. Both H1 and H4 carried five resistance genes [bla OXA, tet(A), tet(B), tet(E), and aac (3)-IIa], whereas H13 only carried the tet(A) gene. The dominant virulence pattern of the three isolates was hlyA + ZapA + luxS + rsbA. The virulence of H1 strain was tested, and its 50% lethal dose (LD50) in mice was 2.29 × 108 CFU ml-1.

Conclusion

To our knowledge, this is the first study to describe an outbreak of bacteremia caused by P. rettgeri in farmed rat snakes.

Significance and impact of the study

The results highlight that P. rettgeri is an emerging bacterial pathogen in farmed reptiles.

Python farming as a flexible and efficient form of agricultural food security

Diminishing natural resources and increasing climatic volatility are impacting agri-food systems, prompting the need for sustainable and resilient alternatives. Python farming is well established in Asia but has received little attention from mainstream agricultural scientists. We measured growth rates in two species of large pythons (Malayopython reticulatus and Python bivittatus) in farms in Thailand and Vietnam and conducted feeding experiments to examine production efficiencies. Pythons grew rapidly over a 12-month period, and females grew faster than males. Food intake and growth rates early in life were strong predictors of total lifetime growth, with daily mass increments ranging from 0.24 to 19.7 g/day for M. reticulatus and 0.24 to 42.6 g/day for P. bivittatus, depending on food intake. Pythons that fasted for up to 4.2 months lost an average of 0.004% of their body mass per day, and resumed rapid growth as soon as feeding recommenced. Mean food conversion rate for dressed carcasses was 4.1%, with useable products (dressed carcass, skin, fat, gall bladder) comprising 82% of the mass of live animals. In terms of food and protein conversion ratios, pythons outperform all mainstream agricultural species studied to date. The ability of fasting pythons to regulate metabolic processes and maintain body condition enhances food security in volatile environments, suggesting that python farming may offer a flexible and efficient response to global food insecurity.

Assessing and improving the veracity of international trade in captive-bred animals

Captive breeding is often seen as a solution to sustainably increasing the supply of individuals in the wildlife trade. To be an effective conservation measure this requires robust systems to verify the authenticity of captive-bred species. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) monitors the international trade in Listed species-which for many taxa is dominated by captive-bred individuals-using the Review of Captive Trade (RCT) process. A key question is how best to identify laundered or inauthentic captive-bred trade and how has this changed over time and space. We develop targeted assessments based on multiple RCT criteria to identify probable instances of laundering and misuse of source and purpose codes in international trade records, and apply this to 39,167 records of captive trade from 2000 to 2020 spanning 53,674,762 individuals. We find a very low proportion of trade volume (1.8%, 37,835 individuals) misreported as originating from non-existent, registered Appendix I-breeding facilities, and low instances of exporter-reported captive trade being recorded by importers as wild-sourced (<4%) or ranched (1%). We also find that <2% of species-year-exporter records have abrupt shifts from wild to captive sources, potentially indicating laundering. Conversely, we find high incidences of exporter- and importer-reported trade differing in whether the trade was commercial or not - a phenomenon we attribute to differing definitions, not illegal activity. Our results indicate a low incidence of concerning international trade being reported, but we suggest this likely stems from reporting requirements that limit our assessments. We highlight additional trade data that, if embedded into Party's annual reports, would vastly improve inferential potential, greatly increasing the number of records (Appendix II and III species) that could be verified with minimal effort for management authorities.

Conservation and cultural intersections within Hong Kong's snake soup industry

Snake soup continues to be an iconic tradition in Cantonese culture. Yet little is known about the relationship between snake soup consumption in Hong Kong, wild snake populations, and the communities depending on this tradition for their livelihoods. We applied an interdisciplinary approach including interviews with shopkeepers and genetic analyses of snake meat samples to determine the species consumed in Hong Kong, their source locations, and shopkeepers’ views on the future of the industry. We genetically identified the common rat snake Ptyas mucosa, widely distributed throughout East and Southeast Asia, and the Javan spitting cobra Naja sputatrix, endemic to Indonesia, as the species most commonly consumed, which was consistent with interview responses. According to interviews, snakes had mostly been imported from mainland China in the past, but now tend to be sourced from Southeast Asia, particularly Indonesia. Interviews also revealed a pessimistic outlook on the continuation of this tradition because of various factors, including a lasting yet misinformed association of snakes with the 2002–2003 outbreak of severe acute respiratory syndrome. Given the COVID-19 pandemic and China's ensuing ban on the consumption of terrestrial wildlife, Hong Kong's snake soup industry will probably continue to rely on Southeast Asian sources to persist. Given the cultural and conservation issues surrounding this tradition, further research on the economic, ecological and social consequences of snake consumption is needed to examine the broader implications of snake soup and similar industries in the region.

Epizootic reptilian ferlavirus infection in individual and multiple snake colonies with additional evidence of the virus in the male genital tract

Reptilian ferlavirus, a pathogen of serious concern in snakes, has been reported in Western countries, but little is known about its prevalence in Thailand, where many snake breeding farms are located. In this study, we investigated the reptilian ferlavirus via swab samples derived from 49 diseased snakes and 77 healthy snakes as well as tissue samples taken from nine dead snakes from five independent snake farms. Using molecular detection, we found the ferlavirus in 8.16% of diseased snakes, but not in healthy snakes. Out of nine farmed snakes, eight snakes derived from four farms were found to be positive. Four complete genome sequences of the ferlavirus were successfully obtained and phylogenetically clustered to the highly pathogenic ferlavirus. Tissue tropism of the ferlavirus was identified in various epithelial cell types using the in situ hybridization technique. Interestingly, the hybridization signals were strongly labeled in the male genital tract. Transmission electron microscopy was used to support the ferlaviral localization in the male genital tract. This study provides the first evidence of ferlavirus localization in the male genital tract and contributes to the knowledge about ferlavirus epidemiology, indicating that there needs to be further awareness and elucidation regarding vertical transmission of reptilian ferlavirus.

Wildlife Farms, Stigma and Harm

Wildlife farming, the commercial breeding and legal sale of non-domesticated species, is an increasingly prevalent, persistently controversial, and understudied conservation practice. The adoption or rejection of wildlife farms is a complex process that incorporates numerous ethical considerations: conservation, livelihoods, animal welfare, and cultural practices. This paper uses qualitative interview data with key informants (academics) to analyze (a) the harms and benefits of wildlife farms and (b) the factors that influence whether wildlife farms are stigmatized or accepted. In evaluations of wildlife farming's harms and benefits, respondents incorporated multiple considerations: animal welfare, environmental impacts, scale disparities between sustenance and commercial farms, consumer preferences, species differences, the substitutability and accessibility of wildlife products, and governance. The results further indicated that the stigmatization or acceptance of wildlife farms is affected by the "wildlife farm" label, if there is a stigma around use of a species, a form of production, or the perceived quality of a wildlife product, cultural differences in wildlife use, wildlife consumer typology, geopolitical factors, and demand reduction efforts. This paper analyzes the complexities of wildlife farming such that stakeholders can understand the impacts of this practice on species, human communities, individual animals, and the legal and illegal wildlife trades.

Molecular identification and phylogenetic analysis of Cryptosporidium, Hepatozoon and Spirometra in snakes from central China

Snakes are popular as food and traditional medicine in China. However, information about parasitic and bacterial infections in snakes from China is scarce. We investigated the prevalence of selected zoonotic agents including Cryptosporidium, Hepatozoon and Spirometra, in snakes in central China from June to October in 2018 by PCR amplification using parasite-specific primers. PCR amplification and DNA sequencing showed that 10.1% (15/149) of snakes were positive for Cryptosporidium spp., while 2.7% (4/149) were positive for Hepatozoon. Additionally, we found 36.9% (55/149) of snakes were infected with Spirometra erinaceieuropaei. The spargana burden per infected snake ranged from 1 to 26. BLAST and phylogenetic analysis of small subunit ribosomal RNA (SSU rRNA) gene and 60-kDa glycoprotein (gp60) gene showed that the parasites belonged to Cryptosporidium parvum genotype IIdA15G1, C. baileyi, C. serpentis and a Hepatozoon species. We conclude that intensively farmed snakes excrete C. parvum and C. baileyi oocysts due to ingestion of infected feeder animals, and that wild snakes in central China were commonly infected with S. erinaceieuropaei, suggesting that eating improperly cooked snakes could be risky to human health.

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Cryptosporidium parvum and C. baileyi were reported in farmed snakes in China for the first time.

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C. serpentis was detected for the first time in Ptyas dhumnades and Gloydius brevicaudus.

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A tentative new Hapatozoon species was first time recorded in wild Lycodon rufozonatus and G. brevicaudus.

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Spirometra erinaceieuropaei infection was found common in wild snakes from central China.

The challenges and conservation implications of bear bile farming in Viet Nam

Legalized trade in commercially farmed wildlife products is sometimes promoted as a conservation strategy. In theory, flooding the market with cheaper or better quality products will decrease the profitability of poaching. Bear bile is highly sought-after for use in traditional medicine and overhunting to supply the demand for bear parts has led to declining populations across South-east Asia. Bear bile farming was established to help supply the high demand for bear bile. In Viet Nam it is legal to keep registered bears, but illegal to extract or sell bear bile. We conducted semi-structured interviews with 66 bear bile farmers in Viet Nam to examine the conservation implications of bear bile farming. The results show that demand for wild bear bile was not satisfied by the widespread availability of farmed bear bile. Farmers report a strong consumer preference and willingness to pay more for wild-sourced products. The existence of bear bile farms presents considerable challenges to law enforcement. The results suggest that bear bile farming in Viet Nam relies on restocking from wild populations, and farmers openly admit to extracting and selling bear bile, in clear violation of national legislation. The case of bear bile farming in Viet Nam provides an example of wildlife farming failing to reduce pressure on a once widely distributed and relatively abundant species. Research into consumer values, attitudes and behaviours will help to improve understanding of market drivers and help inform the design of effective species conservation and management strategies.