VN October 2023

Vetnuus | October 2023 14 underlying diseases, such as human immunodeficiency virus infection and other immune conditions and extant respiratory problems, as well as the elderly, are at increased susceptibility to infection and symptomology [103, 106]. Globally, approximately 10 million people become ill with TB annually, and approximately 1.5–1.8 million die from the disease, a mortality rate of 15–18% [106, 107]. Accounting for novel, persistent, and recurrent cases, approximately 1.8–2 billion people harbor the infection worldwide [105]. Bovine-to-human TB infections are relatively small, accounting for <2% of all TB cases [103, 108]. Essentially, TB is a predominantly human disease and the leading cause of global human infection-related mortality. Tuberculosis and elephants Although captive elephants in zoos, circuses, and tourism are frequently associated with TB [46, 109], as well as free-ranging Asian and African elephants [43, 110], the presence of TB in these animals may result from original human-to-elephant contamination [37, 109, 111]. In elephants, as in humans, signs of TB include fever, coughing, sneezing, pneumonia, breathlessness, malaise, fever, loss of body condition, systemic disease, pain, or death [104, 105]. TB among captive elephant populations is investigated using several methodologies, for example, blood serum sampling and lateral flow serological testing [112] and/or collection of material through trunk washing, culture, and PCR testing [113]. However, current methodologies are limited, and infection rates in populations are difficult to quantify conclusively [114, 115]. One study, using blood serum sampling of approximately 600 captive Asian elephants found a positive TB prevalence rate of 16% [112], and another study, also using serology, found 23% in a captive population [22]. Trunk wash testing of captive Malaysian elephants found a 20% prevalence rate [116]. Despite data limitations, such prevalence rates indicate the importance of TB among elephant populations, not only for their own health but also as a reservoir of potential human and wild elephant epidemics with implications for species conservation in the latter. Viral pathogens and diseases Elephant pox virus Elephant pox virus is a disease caused by a group of orthopoxviruses that are similarly responsible for smallpox, cowpox, monkeypox, and other infections [12, 14, 15, 38, 82, 117, 118]. In humans, the infection results in dermal and mucous membranous signs and symptoms, fever, systemic disease, or death [12, 15, 30]. In elephants, the infection results in disseminated dermal ulceration, mucosal membrane lesions, tongue lesions, debilitation, or death [82]. Transmission can occur through bites, direct contact, and aerosolized particle routes [12, 15, 30]. Little is known regarding the prevalence of the pox virus in elephants. However, the diversity, geographic distribution, and adaptability of orthopoxviruses in general and the range of animal species involved lead them to be considered one of the world’s most significant potential epidemic and pandemic threats to both animals and people [38]. The latest pandemic concern monkeypox [119] exemplifies the nature of orthopoxviruses and has been declared as a public health emergency of international concern [120]. Parasitic pathogens and diseases Cryptosporidiosis Cryptosporidiosis is adisease causedby a rangeof Cryptosporidiumspp. microparasites. In humans, the infection results in gastrointestinal signs and symptoms, fever, malaise, anorexia, weight loss, pain, septicemia, meningitis, or death [121, 122]. There is little information regarding the disease in elephants, but signs of infection might be presumed to reflect those observed in humans and other animals. Cryptosporidium spp. is commonly found in many environments, including soil, water, and animals [121, 122], and over 25% of African elephants may harbor the organism [123]; thus, individuals may be asymptomatic carriers. Transmission occurs through ingestion of contaminated water, fomite transfer, and fecal-oral ingestion [121, 122]. The parasites are widely present across various species, including elephants and humans, and geographical regions [18, 83]. Cryptosporidiosis is an emerging zoonotic infection, increasingly reported across species and regions [33]. Helminthiasis Helminthiasis refers to several pathogenic parasitic infections or infestations caused by a wide range of invasive macroscopic worms [86, 124]. The infection results in widely varied signs and symptoms in humans, including gastrointestinal, cardio-respiratory, malaise, anorexia, weight loss, fever, systemic disease, or death [30, 85, 86]. In elephants, individuals may be asymptomatic carriers, but infection results in debilitating gastrointestinal conditions [86]. Helminth parasites are extremely common in wild and captive animals, with 96% prevalence being found in some African elephant populations [86]. Many helminths have complex lifecycles, meaning that diverse transmission routes may be involved, although frequently these include fomite, fecal-oral, food, water, and soil [30, 85, 86]. Toxoplasmosis Toxoplasmosis is a disease caused by Toxoplasma gondii and occurs widely in animals and humans [28, 39, 87, 88]. In humans, the infection results in a range of signs and symptoms, including gastrointestinal, malaise, anorexia, weight loss, pain, fever, systemic disease, or death, and transmission is characteristically fecal-oral, through contaminated soil, or fomites [28, 39, 87, 88]. In elephants, individuals may be asymptomatic carriers, but infection may result in debilitating gastrointestinal and systemic disease conditions [125]. Relatively little is known regarding disease incidence or prevalence [23, 32], although one study found antibodies in 45.5% of Asian elephants, indicating that animals had, at some point, been exposed to the pathogen [125]. Another study also showed widespread exposure but with no determination regarding the source of infection [39]. Public health and safety summary Because detailed data on public health at the elephant-human interface in tourism are lacking, an evaluation of risk was conducted both for elephants as a species as well as the 12 pathogens/diseases cited in Table-1 using the zoonoplasticity intuitive risk algorithm [74]. The zoonoplasticity algorithm for elephant species provided a public health and safety risk factor score of 22–27 points and a rating of“High.” The five-point range arises due to the addition of five points where vulnerable human groups (e.g., under 5 years, immunocompromised, elderly, pregnant) may be involved. The zoonoplasticity intuitive risk algorithm test results for the 12 pathogens or diseases fromTable-1 are provided in Table-2 and are intended to offer a “ball park” analysis of possible risk. Elephant tourism: An analysis and recommendations for public health, safety ...... <<< 13