An incursive , dog - killing leech is now lurking in Southern California . In new inquiry this workweek , scientists say they ’ve confirmed the newfound spread of the flatworm Heterobilharzia americana to the arena . The parasite is not thought to be a risk to human beings , but it could become an emerging menace to pets and animals living along the lengthy Colorado River , the researchers say .
H. americana is one of many louse species dub the liver trematode worm . Their immediate hosts are escargot , which pack and unloosen the larval , free - living form of the parasites into fresh water . Once these larvae come across their next compatible victim ( also called a definitive host ) in the H2O , they burrow their way in through the skin , migrating first to the lungs , the liver , and then certain blood vessel along the intestinal liner . From there , they mature into adult , better half , and lay testicle that are pooped out and intended to taint snails , lead off the life cycle all over again . Raccoons are the primary unequivocal emcee of the species , but the worms can infect and set eggs inside other mammals as well , include dogs and horses .
When these worm taint dogs , they cause a disease calledcanine bilharziasis . Most of the damage triggered by this infection does n’t come from the worms that first invade the soundbox , but the next generation of eggs they dwell , which circulate through the blood stream and can finish up in the intestine and other organs . They then touch off kindling and the shaping of resistant cellphone clusters called granulomas that can damage the trunk . Symptoms incline to be gradual at first , such as lethargy and weight loss , but without intervention , the infection can lead to life - threaten organ failure .
Image: Paul’s Lady (Shutterstock)
It was previously reckon that the worms only had one coinage of escargot that of course served as an immediate host , Galba cubensis , but scientists have recently come across at least two and possibly three other snail species that can acquit it . likewise , while cases of dog contagion have historically been escort in parts of Texas and other res publica around the Gulf Coast , veterinarians and best-loved owners have now started to report case elsewhere , including in California . From 2018 to 2023 , 11 cases have beenreportedin the res publica , all from Southern California and all tied to dog that had visited the Colorado River , whichsuppliesup to a third of the orbit ’s water system .
flatworm like H. americana are n’t normally the metier of study generator Adler Dillman , a professor of nematology ( the study of roundworm ) at the University of California , Riverside . But he did n’t go along up the hazard to enquire the mysterious comer of these case when his colleagues ask him for helper .
Dillman and his team decided to look for H. americana in its presumed newfangled hunting grounds . They went to part of the river where domestic dog cases had in all probability occurred and collected samples of snails that they took back to their science lab , hope to catch some worm right as they were about to be moult from the snails .
An illustration of the worm’s complex life cycle by the study authors.Illustration: Baniya, et al/Pathogens.
“ It was kind of like looking for a phonograph needle in a haystack , since we were trying to pick up snail that had been infected around three weeks before … And when we saw [ the worms ] , we were all jumping up and down excited take picture . It was a electrifying minute for us , ” Dillman tell Gizmodo . “ But that ’s bad news show for people living in and around that area , because now there ’s this sponger to be concern about . ”
The researchers also sequence the deoxyribonucleic acid from the snails and louse , finding the clear front of H. americana inside not one but two escargot species , G. cubensis and Galba humilis — an unexpected discovery for multiple reasons .
“ First of all , these snails have n’t been reported in the Colorado River before , certainly not this far south . And it was unusual for us to find both of these coinage co - occurring in the same spot , which also has n’t previously been reported , ” Dillman pronounce .
There are other species of worms that causeserious schistosomiasisin humans , but photo to H. americana only seems to cause a mild skin roseola at most . And the transmission can not be spread from dog to dog or from domestic dog to mankind , only through direct link with the worms in contaminated freshwater .
But the worms do seem to have become a larger risk to dogs and other creature than once assume . There have been recently account infections in other non - autochthonous country of the body politic close to the Colorado River , so it ’s very potential that the river is broadcast the snails and the worms far and broad .
“ This could be a much bigger problem — not just in Southern California , but Nevada , Utah , Colorado , ” and the voice of New Mexico tied to the river , Dillman said .
Another unrequited question is precisely how these snail ended up in the river in the first post . “ Climate change may be a ingredient , but human natural action could also for certain be a factor as well . We just do n’t make love , ” Dillman said .
For now , the scientist hope their work can facilitate keep dogs and their owners secure from the sponge .
“ It ’s good to live that this is a possibility . And so you may want to go to a different office , you may not want to be in this part of the Colorado River . Or maybe you may just be capable to keep a closer middle on your pawl and know what the possible cause is of any illness that pops up , ” Dillman said .
While Dillman mostly process with nematode worm , he would like to keep examine H. americana if he can . roundworm and the infections they make are often used to learn more about how the immune system works , but there may be unique lessons that these and similar flatworms could teach us as well , he notes .
Tropical disease
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