Soil-transmitted helminth infections are mostly seen in warm, humid climates with inadequate sanitation and hygiene (CDC 2020). Snails are found on dirt either scavenging for food or reproducing; as a result, parasites may infect snails. A total of seventy (70) snails (Archachatina marginata) were studied in this study, with an overall prevalence of 48.57%. In the investigation, only Angiostrongylus cantonensis was discovered. Geohelminths such as hookworm, Enterobius vermicularis, and Ascaris lumbricoides, which are prevalent soil parasites in these places (Awosolu et al. 2020), did not infect snails. As a result, the adaptation of A. cantonensis as a significant parasite of these land snails requires more research. This nematode has been found in big African land snails in other parts of the world (Kim et al. 2014; Iwanowicz et al. 2015).
The rat parasite A. cantonensis is the cause of the developing infectious neurologic rat lungworm illness (Jarvi et al. 2012). As a result, A. maginata is implicated as the most likely intermediate host of A. canonensis. Humans are vulnerable to the effects of A. cantonensis infection, especially if infective larvae are consumed (Chatterjee 2009). The majority of the damage in human-infected cases is evident in the intestinal walls, resulting in abdominal discomfort and fever. Both humans and animals have been diagnosed with eosinophilic meningoencephalitis (Morassutti et al. 2014).
The snail samples were divided into three groups based on their size: 20 large, 20 middle, and 30 little. Small snails were the most affected, with an infection rate of 18 (52.94%), followed by medium snails with a rate of 10 (29.41%), and large snails with a rate of 6 (6.2%) (17.65%). This contradicts the findings of Odaibo et al. (2000), who found that A. marginata snails were the most infected with A. cantonensis. Rezac et al. (1993), who also documented a drop in helminthic infection of A. marginata as they grew larger, attributed this to mucus suppression of larvae infectivity as the snails grew larger, explained the high prevalence of A. cantonensis in small snails.
The highest prevalence of infection was found on the infected snails' mantle, followed by the digestive gland, kidney, and stomach; no infection was found on the crop, haemolymph, or foot. The high parasite prevalence in the mantle, digestive gland, and kidney could be owing to these organs' high vascularization and plenty of easily accessible nutrients (Madsen 1982). The location of A. marginata had a significant impact on the infection's prevalence. Because the snails gathered near dumping locations had a larger worm burden than those obtained in the bushes.
Angiostrongylus cantonensis was identified as the nematode with the flimsy, slender, and simple mouth and no lip or buccal cavity. Angiostrongylus cantonensis parasite resides primarily in rodents like rats, but it can also infect snails and slugs that come into touch with contaminated rat feces (Igbinosa et al. 2006). Ingestion of raw or undercooked contaminated mollusks, crustaceans, or other hosts, as well as vegetables contaminated with infectious larvae, can cause infection. These larvae go up the trachea, where they are ingested and ejected along with the feces. For several weeks, they remain viable and infectious in excrement or freshwater (Hu et al. 2011). Only if these larvae are eaten by a mollusk intermediate host does the life cycle come to an end (land snails or slugs). The larvae mature into infectious third-stage larvae in about 2 weeks, and the mollusks remain infected for the rest of their lives. Shrimp, fish, crabs, frogs, predacious land planarians, and monitor lizards can all eat diseased mollusks and act as paratenic hosts. Rodents become infected after ingesting either mollusks or paratenic hosts (Chatterjee 2009). Ingesting uncooked contaminated intermediate or paratenic hosts or vegetables contaminated with third stage larvae can infect humans (dead end hosts) (Chatterjee 2009).
The infection might be minor, and mortality is uncommon. When infective A. cantonensis larvae are consumed, they infiltrate intestinal tissue and cause enteritis. Before reaching the neurological system, the larvae pass through the liver and lungs. Cough, rhinorrhoea, sore throat, malaise, and fever might occur as the worm progresses through the lungs. The predominant clinical manifestation of eosinophilic meningitis is headache, neck stiffness, parasthesia, vomiting, fever, nausea, and impaired vision or diplopia after the nematode enters the central nervous system (CNS) after around 2 weeks. Children may also feel sleepy, and experience abdominal pain, or weakness of the extremities. Eosinophilic pleocytosis, eosinophilic encephalitis and ocular angiostrongyliasis may also occur.