Prevalence of Angiostrongylus cantonensis among different species of snails in the village of Bagong Sikat Muñoz, Nueva Ecija, Philippines and its associated risk factors for zoonotic transmission

Diversity, infection dynamics, and environmental drivers of gastropods in the rice field-lakescape of Lake Mainit, Philippines: implications for snail-borne diseases and integrated management strategies

Rice fields near Lake Mainit, Philippines, serve as ecological hotspots for gastropod diversity and parasitic infections, particularly schistosomiasis. This study examined the cascading effects of soil and water parameters on snail diversity and abundance, as well as the influence of environmental factors on the infection status of dominant gastropod species. A total of ten gastropod species from six families were identified across six stations, with Melanoides maculata as the most abundant (32%). Oncomelania hupensis quadrasi, the snail intermediate host of Schistosoma japonicum in the Philippines, was present at all stations, with varying cercarial infection rates. Soil analysis revealed compositions of 25% clay, 20% pebbles, and varying sand and gravel proportions, with acidic conditions (pH 3.04 in Matin-ao). Nickel concentrations exceeded safety thresholds in Magpayang (162 ± 45.1 ppm) and Matin-ao (148 ± 1.67 ppm), alongside elevated calcium, magnesium, manganese, and copper levels in Alipao, Cuyago, and San Isidro. Principal component analysis (PCA) identified sodium, calcium, potassium, pH, and temperature as key environmental drivers, though they influenced site differentiation more than snail species and abundance. To assess parasite transmission, a chi-square test of independence revealed a significant association between snail species and infection rates across sites. Oncomelania hupensis quadrasi exhibited consistently high deviation values in Magpayang, Cuyago, San Isidro, and Alegria, indicating localized infection patterns. These findings highlight the interplay between physico-chemical factors, gastropod communities, and parasite transmission, providing baseline data crucial for targeted snail control and schistosomiasis prevention in Philippine rice fields. Further investigation is needed to understand how environmental contamination from infected bovines sustains schistosome transmission in unfavorable rice field conditions.

Prevalence of Angiostrongylus cantonensis in definitive and intermediate hosts collected from agricultural areas in Ampayon, Butuan City, Southern Philippines

Angiostrongyliasis is a parasitic disease and a leading cause of human eosinophilic meningoencephalitis caused by rat lungworm Angiostrongylus cantonensis. This parasite infects a wide range of animal hosts, including snails and rats, which plays a significant role in zoonotic transmission. The study was conducted to determine the prevalence of A. cantonensis infection in freshwater snails and definitive rat hosts in the agricultural area in Ampayon, Butuan City, Philippines. A total of 54 rat samples and 719 snail individuals were collected in June and July 2020. An overall 2.36% prevalence rate of A. cantonensis snail infection was recorded, consisting of Pomacea canaliculata and Melanoides tuberculata, with a prevalence rate of 4.05% and 1.38%, respectively. Results revealed an overall prevalence of 38.9% in rat infection. Rattus tanezumi (48.48%) showed a higher infection than Rattus norvegicus (23.80%). Higher infection rates were found in rice field environments than residential houses, with 44.12% and 30% prevalence rates, respectively. Moreover, male rats showed higher infection rates (50%) than female rats (26.92%). Among age classes, adult rats had significantly higher infection rates (48.57%) than juvenile rats (21.05%). Correlation analysis showed a significant positive correlation between A. cantonensis infection intensity to the body length (r = 0.603; p = 0.001) and body weight (r = 0.715; p = 0.000) of rats. The study exemplifies the critical role of intermediate and definitive hosts for angiostrongyliasis. Infected freshwater snails and rats in rice fields make these agricultural areas a venue for A. cantonensis emergence. Integrated actions, health education campaigns, surveillance, hygiene, and good farming practices will help prevent the potential risk of the transmission of angiostrongyliasis in the area.

Predicting Current Potential Distribution and the Range Dynamics of Pomacea canaliculata in China under Global Climate Change

Simple Summary

Pomacea canaliculata is one of the 100 worst invasive alien species in the world, causing significant effects and harm to native species, ecological environment, human health, and social economy. In this study, we used species distribution modeling (SDM) methods to predict the potential distribution of P. canaliculata in China and found that with climate change, there would be a trend of expanding and moving northward in the future.

Abstract

Pomacea canaliculata is one of the 100 worst invasive alien species in the world, which has significant effects and harm to native species, ecological environment, human health, and social economy. Climate change is one of the major causes of species range shifts. With recent climate change, the distribution of P. canaliculata has shifted northward. Understanding the potential distribution under current and future climate conditions will aid in the management of the risk of its invasion and spread. Here, we used species distribution modeling (SDM) methods to predict the potential distribution of P. canaliculata in China, and the jackknife test was used to assess the importance of environmental variables for modeling. Our study found that precipitation of the warmest quarter and maximum temperature in the coldest months played important roles in the distribution of P. canaliculata. With global warming, there will be a trend of expansion and northward movement in the future. This study could provide recommendations for the management and prevention of snail invasion and expansion.