Gnathostoma spp. (Gnathosthoma spinigerum, Gnathostoma doloresi, Gnathostoma hispidum and Gnathostoma nipponicum)
Gnathostoma spinigerum is a nematode which infects various types of animals (canines and felines, and probably pigs), and can infest man (gnathostomiasis) with manifestations like eruptions, larva migrans, edema Yangtze vagrant swelling, .... The acquired infection in both animals and humans, by eating freshwater fish (Ophicephalus argus and O. tadianus) raw or undercooked, but also, though less frequently, with meat of some animals such as domestic ducks ( Anas platyrhynchos) or domestic chicken (Gallus gallus), when they have been fed with raw fish.
Gnathostoma spinigerum has a multi-host life cycle. The final hospeador (with adult helminths) are several species of animals. They eliminate the eggs when they are released freshwater larvae which are ingested by a -copépodos- microscopic crustaceans of the genus Cyclops. Shellfish are eaten by small fish, and these in turn are eaten by carnivorous animals like dogs or cats. The larva penetrates the stomach wall and migrates through the body of dog or cat (or other carnivores) to return after about 3 months to the stomach, the gastric mucosa where it is fixed. After about 6 months mature, copulating and the females lay eggs that are eliminated by feces reaching the water to start the cycle again.
Humans are unusual for host larvae ingested, so they do not mature in people. However, they may roam our organism causing changes depending on where they are (larva migrans).
This parasite is most common in Thailand, but is found in several places in Southeast Asia, besides Japan, Australia, USA, and Mexico. However its incidence is rare outside Asia.
Features helminto: 11 to 54 mm, with globular head with a pair of side lips surrounding the mouth. Cephalic region is covered by transverse rows of thorns. The body is pink, and is also covered in its earlier by flat spines are scattered along the body part. On the back are also small spines
Four species are causing human gnathostomiasis: G. doloresi, G. hispidum, nipponicum G. and G. spinigerum.
The most effective prevention is to avoid eating raw or undercooked fish. The only treatment that has demonstrated an experimental reduction has been albendazole.
Microbiological diagnostic tests
- In definitive hosts (dogs, cats, pigs): stool watching eggs.
- In natural intermediate host fish: tissue samples.
- People in aberrant hosts intermediaries samples affected areas where you can meet their DNA.
Tests in IVAMI
- Microscopic observation of helminth eggs after concentration.
- Observation of larval stages in host fish intermediaries.
- Molecular detection of genes Gnathostoma spp. and identification by sequencing.
Recommended samples for microbiological diagnosis
- Feces intermediate hosts: dogs, cats, pigs, ...
- Fish tissues suspected of transmitting the infection.
- Cerebrospinal fluid, tissue exudate, exudate or skin biopsy, ... or other inflammatory areas where they are.
Preservation and shipment of sample:
- Refrigerated (preferred) for less than 2 days.
- Frozen: over 2 days.
Delivery of results
- Microbiological molecular diagnostics - 48 hours
Cost of the test
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