The article reports the discovery of a deadly dog parasite, Heterobilharzia americana, in Southern California for the first time. This parasitic worm, typically found in Gulf Coast and South Atlantic states, was identified near the California-Arizona border along the banks of the Colorado River. This finding marks the westernmost extent of the worm’s distribution in the United States.
Canine schistosomiasis, caused by H. americana, is a potentially fatal disease in dogs. However, prompt diagnosis and treatment with deworming drugs like praziquantel can be effective in managing the infection. While the parasite doesn’t cause schistosomiasis in humans, it can cause skin irritation known as “swimmer’s itch.”
The study was initiated after a cluster of dog illnesses, including one fatality, was reported in Southern California counties. Dogs that fell ill had all previously swum in the Colorado River near the California-Arizona border, indicating the river as a potential source of infection.
Researchers conducted surveys near Blythe, California, to investigate the presence of the parasite. They collected freshwater snails, known hosts of the worm, and found that some snails contained DNA from the parasitic worms in their free-swimming stage. However, estimating the overall prevalence of infected snails in the river was challenging due to the immature stage of many worms found in the snails.
The study suggests that H. americana may be present in other Colorado River tributaries in nearby states, warranting further investigation. The researchers emphasize the importance of awareness among Californians regarding the risks of canine schistosomiasis and urge pet owners to watch for early symptoms in their dogs, such as lethargy, loss of appetite, weight loss, vomiting, and bloody diarrhea.
Despite the presence of the parasite in the area, the researchers advise pet owners to be vigilant rather than avoiding the area altogether. They highlight the need for continued monitoring and research to better understand the extent of the parasite’s distribution and its impact on both animal and human health.
