A POTENTIAL ZOONOTIC PARASITE: CRYPTOSPORIDIUM PARVUM TRANSMISSION IN RATS, PIGS AND HUMANS IN WEST LOMBOK, INDONESIA

Emerging zoonotic diseases in Southeast Asia in the period 2011-2022: a systematic literature review

As COVID-19 has shown, pandemics and outbreaks of emerging infections such as Zika, Nipah, monkeypox and antimicrobial-resistant pathogens, especially emerging zoonotic diseases, continue to occur and may even be increasing in Southeast Asia. In addition, these infections often result from environmental changes and human behaviour. Overall, public health surveillance to identify gaps in the literature and early warning signs are essential in this region. A systematic review investigated the prevalence of emerging zoonotic diseases over 11 years from 2011 to 2022 in Southeast Asia to understand the status of emerging zoonotic diseases, as well as to provide necessary actions for disease control and prevention in the region. During the 2011-2022 period, studies on pigs, poultry, ruminants, companion animals and wildlife in Southeast Asia were reviewed thoroughly to assess the quality of reporting items for inclusion in the systematic review. The review was performed on 26 studies of pigs, 6 studies of poultry, 21 studies of ruminants, 28 studies of companion animals and 25 studies of wildlife in Southeast Asia, which provide a snapshot of the prevalence of the emerging zoonotic disease across the country. The findings from the review showed that emerging zoonotic diseases were prevalent across the region and identified a few zoonotic diseases associated with poultry, mainly stemming from Cambodia and Vietnam, as high priority in Southeast Asia.Clinical relevance: Appropriate prevention and control measures should be taken to mitigate the emerging zoonotic diseases in Southeast Asia.

Critters and contamination: Zoonotic protozoans in urban rodents and water quality

Rodents represent the single largest group within mammals and host a diverse array of zoonotic pathogens. Urbanisation impacts wild mammals, including rodents, leading to habitat loss but also providing new resources. Urban-adapted (synanthropic) rodents, such as the brown rat (R. norvegicus), black rat (R. rattus), and house mouse (Mus musculus), have long successfully adapted to living close to humans and are known carriers of zoonotic pathogens. Two important enteric, zoonotic protozoan parasites, carried by rodents, include Cryptosporidium and Giardia. Their environmental stages (oocysts/cysts), released in faeces, can contaminate surface and wastewaters, are resistant to common drinking water disinfectants and can cause water-borne related gastritis outbreaks. At least 48 species of Cryptosporidium have been described, with C. hominis and C. parvum responsible for the majority of human infections, while Giardia duodenalis assemblages A and B are the main human-infectious assemblages. Molecular characterisation is crucial to assess the public health risk linked to rodent-related water contamination due to morphological overlap between species. This review explores the global molecular diversity of these parasites in rodents, with a focus on evaluating the zoonotic risk from contamination of water and wasterwater with Cryptosporidium and Giardia oocysts/cysts from synanthropic rodents. Analysis indicates that while zoonotic Cryptosporidium and Giardia are prevalent in farmed and pet rodents, host-specific Cryptosporidium and Giardia species dominate in urban adapted rodents, and therefore the risks posed by these rodents in the transmission of zoonotic Cryptosporidium and Giardia are relatively low. Many knowledge gaps remain however, and therefore understanding the intricate dynamics of these parasites in rodent populations is essential for managing their impact on human health and water quality. This knowledge can inform strategies to reduce disease transmission and ensure safe drinking water in urban and peri‑urban areas.

Global prevalence of Cryptosporidium spp. in pigs: a systematic review and meta-analysis

Cryptosporidium spp. are significant opportunistic pathogens causing diarrhoea in humans and animals. Pigs are one of the most important potential hosts for Cryptosporidium. We evaluated the prevalence of Cryptosporidium in pigs globally using published information and a random-effects model. In total, 131 datasets from 36 countries were included in the final quantitative analysis. The global prevalence of Cryptosporidium in pigs was 16.3% (8560/64 809; 95% confidence interval [CI] 15.0–17.6%). The highest prevalence of Cryptosporidium in pigs was 40.8% (478/1271) in Africa. Post-weaned pigs had a significantly higher prevalence (25.8%; 2739/11 824) than pre-weaned, fattening and adult pigs. The prevalence of Cryptosporidium was higher in pigs with no diarrhoea (12.2%; 371/3501) than in pigs that had diarrhoea (8.0%; 348/4874). Seven Cryptosporidium species (Cryptosporidium scrofarum, Cryptosporidium suis, Cryptosporidium parvum, Cryptosporidium muris, Cryptosporidium tyzzeri, Cryptosporidium andersoni and Cryptosporidium struthioni) were detected in pigs globally. The proportion of C. scrofarum was 34.3% (1491/4351); the proportion of C. suis was 31.8% (1385/4351) and the proportion of C. parvum was 2.3% (98/4351). The influence of different geographic factors (latitude, longitude, mean yearly temperature, mean yearly relative humidity and mean yearly precipitation) on the infection rate of Cryptosporidium in pigs was also analysed. The results indicate that C. suis is the dominant species in pre-weaned pigs, while C. scrofarum is the dominant species in fattening and adult pigs. The findings highlight the role of pigs as possible potential hosts of zoonotic cryptosporidiosis and the need for additional studies on the prevalence, transmission and control of Cryptosporidium in pigs.