Angiostrongylus cantonensis (A.cantonensis) is a zoonotic parasitic nematode, with a worldwide distribution, causing eosinophilic meningitis or meningoencephalitis in humans. Humans infection with A.cantonensis typically occur from intentional or unintentional ingestion of infected intermediate or paratenic hosts, sometimes due to contaminated produce.
Traditionally, with the wider domain of climate and health, the neglected tropical diseases (NTDs), are a collection of infectious diseases affected hundreds of millions of individuals living in tropical and subtropical countries. Recently, such dramatic habitat changes are linked to accelerated biodiversity loss, which has been linked to major changes in the epidemiology of human diseases: increased disease risks and the emergence of novel pathogens resulting from increased contacts among wildlife, domesticated animals, and humans[1–3]. In particular, angiostrongyliasis, as a kind of NTDs, was found in the Pacific Islands, Southeast Asia, parts of South and Central America and the Caribbean, even in European countries[4–6]. Recently, although researchers gradually pay more attention to investment towards reducing the burden of NTDs, they still collectively contribute to productively loss, illness and suffering in many countries[7, 8]. Recent estimates of their overall burden suggest NTDs kill over 350,000 people per annum and cause the loss of between 27 and 56 million disability-adjusted life years. To date, more than 2000 cases of eosinophilic meningitis have been recorded in China, even 100 cases in Taiwan and most human cases of angiostrongyliasis (~ 1300 cases) have been reported in Thailand[5, 10], where between 0.3 and 2 people per 100,000 become infected annually[11, 12]. These findings indicate that the extensive distribution of A.cantonensis in globally is high, thus putting humans as a higher risk of A.cantonensis infection.
In recent decades, more than 20 species of feral rodents have been categorized as pests in tropical and subtropical countries, and these species cause tremendous losses and damages to crops and food stocks. Feral rodents are known to transmit diseases and act as reservoir hosts to many zoonotic parasites that pose health risks to humans, including A.cantonensis, hantaviruses, Leptospira spp., Bartonella spp., Trypanosoma spp., and Babesia spp.[14–16]. For A.cantonensis, at least 17 rodent species may behave as definitive hosts, capable of passing first stage larvae (L1) in their feces. Simultaneously, snails and slugs (intermediate hosts) ingest these larvae, which mature into the third stage larvae (L3) (infective form) that are passed on to the definitive hosts again when the definitive hosts consume infected intermediate hosts. Then, the worms travel to brain, especially in the subarachnoid space, elicits an intense eosinophilic inflammation and causes acute eosinophilic meningitis. Humans become the incidental hosts by consuming the infected intermediate or paratenic hosts (or ingestion of snail slime). Importantly, the development of control methods against zoonotic parasites depends on knowledge of their life cycles and transmission patterns in different zoogeographical regions. Therefore, it is essential to survey the relationship between parasites and rodents in order to identify the sources of zoonotic infections.
Surprisingly, despite rodents being the dominant vertebrate species in many of these altered tropical systems and the key hosts for numerous zoonotic microparasites (viruses, bacteria, and protists), consistent patterns between habitat fragmentation and environment change with the epidemiology of multiple parasite diseases have yet to be determined, and studies that address the context of pathogen circulation are lacking. Indeed, simultaneous to the technical and targeted approaches being, recommended by WHO are much wider attempts at sustainable development, most visible through the lens of the sustainable development goals. Meanwhile, there are little diagnostic methods and effective treatment methods. Furthermore, we need do more research to solve this challenge. Here, in this study, we aim to identify the prevalence of A.cantonensis in rodent hosts in China and several Asian countries, providing essential recommendations for the researchers and policy makers.