The first case of Echinococcus canaden exinococcus…
A parasite in Norway Echinococcus canadensis G10 was found in a moose found dead in Innlandet County. It was sampled by the Norwegian Food Safety Authority as part of a routine slaughter inspection. An animal in good general condition has cysts in the lungs.
This is the first time this parasite has been detected in moose in Norway, E. canadensis G10 has not been detected in Norway before, but has been detected in Sweden and Finland. In Finland, it was also the cause of human strife.
in nature, E. canadensis is sylvatic and semi-synthropic in nature, with a life cycle involving wild deer (including moose) as intermediate hosts and canids (dogs, coyotes, and wolves) as definitive hosts. Echinococcosis can infect humans, but the Public Health Institute believes that the risk of infection is very low.
Reminders of cystic echinococcosis or hydatidosis
Human echinococcosis is a zoonosis (a disease transmitted from animals to humans) caused by parasites, namely tapeworms. Echinococcus. Echinococcosis occurs in 4 forms:
- Cystic echinococcosis, also known as hydatid disease or hydatid disease, is caused by an invasion by a central type complex. Echinococcus granulosus ;
- alveolar echinococcosis, as a result of infection E. multilocularis ;
- Two forms of neotropical echinococcosis: polycystic echinococcosis caused by E. vogeli ; and caused by unicystic echinococcosis E. oligarthrus.
Cystic echinococcosis is present on all continents except Antarctica, especially in the countries of the Mediterranean basin, North Africa, Latin America, Australia, New Zealand, China and Central Europe.
The parasite cycle consists of two stages: the intermediate host (HI) and the definitive host (HD).
A number ofherbivores and omnivores act like intermediate hosts for Echinococcus. They become infected by ingesting the embryonated eggs (embryophores) of the parasite present in the external environment (food and water), and then pass to the larval stage in the internal organs. The larvae pass through the digestive wall and reach the liver and even other organs where they develop with the bloodstream.
The carnivores act like definitive hosts for the parasite and harbors an adult tapeworm in its intestines where it will lay its eggs. These definitive hosts become infected by ingesting the internal organs of intermediate hosts that contain parasite larvae.
The people there is random intermediate hosts. They become infected after direct contact with a dog (licking, caressing), and more rarely indirectly by ingesting embryophores from contaminated food or water. Eggs penetrate the digestive wall and reach the liver through the bloodstream. More rarely, they can reach other organs.
Currently, Based on the phylogenetic analysis and specificity in the life cycles of the parasitic hosts, 5 species are distinguished within the complex. Echinococcus granulosus sensu lato. : E. granulosus serious talker E. equinus, E. ortleppi, E. canadensis and E. felidis (Parasite Vectors. 2022 Mar 28;15(1):109.doi:10.1186/s13071-022-05197-8.)
- E. granulosus sensu stricto. containing genotypes G1 and G3, previously described as “sheep strain” and “buffalo strain,” respectively. The G2 genotype is no longer considered a valid genotype, but is recognized as a microvariant of G3. E. granulosus ss is distributed worldwide due to both the low specificity of HI and the extensive livestock trade. The main HIs and HDs contributing to the maintenance of the parasite life cycle are ruminants (especially sheep) and dogs (mainly sheepdogs), respectively. E. granulosus ss causes 88.5% of human hydatidosis infections.
- E. equinus represented by the G4 genotype, previously described as a “horse strain”. The main HI and HD are horses and dogs. The species was long thought to be non-zoonotic until two human cases were recently documented in Turkey and Uzbekistan.
- E. ortleppi represented by the G5 genotype, previously described as a “cattle strain”. The main HI and HD are cattle and dogs. This parasitic infection has become rare in animals, and few human infections have been documented worldwide.
- The majority E. canadensis divided into two main layers. G6/7 genotypes (previously described as “camel strain” and “pig strain”, respectively) and G8/G10 genotypes (also referred to as “cervid strains”). The G6/7 genotypes are distributed worldwide and have a rather low specificity of HI, mainly involving domesticated species such as pigs, camels and goats, and dogs such as DH. E. canadensis (G6/7) is the second most important public health species, responsible for approximately 11% of documented human infections worldwide. G8/G10 genotypes have a circumpolar distribution in the northern hemisphere. The main HIs and HDs contributing to the maintenance of the parasite life cycle are wild carrion (such as elk and deer) and wolves, respectively, but also to a lesser extent semidomesticated reindeer and hunting, sledding or herding dogs. Several human infections E. canadensis (G8/G10) have been documented so far. Taxonomic status of the groupE. canadensis (G6/7, G8 and G10) are still under discussion.
- E. felidis (also called the “lion strain”), has a wild life cycle and is found only in sub-Saharan Africa. No human infection has been reported so far.
Human infection E. granulosus results in the development of one or more hydatid cysts, most commonly located in the liver and lungs, and less commonly in the bones, kidneys, spleen, muscles, and central nervous system.
The asymptomatic incubation period of the disease may last for many years before hydatid cysts develop sufficiently to trigger clinical symptoms.
Liver hydatids often cause abdominal pain, nausea, and vomiting. Clinical signs of pulmonary involvement include chronic cough, chest pain, and shortness of breath. Other symptoms depend on the location of the hydatid cysts and the pressure on the surrounding tissues. Nonspecific symptoms include anorexia, weight loss, and asthenia.
There are three therapeutic options for the treatment of cystic echinococcosis:
- Percutaneous treatment of hydatid cysts using the PAIR technique (puncture, aspiration, injection, repeated aspiration);
- anti-infective drug treatment (albendazole).
Cystic echinococcosis is a preventable disease because the definitive and intermediate hosts are domestic animals. Prevention is based on the following measures:
- public education;
- periodic deworming of dogs with praziquantel (at least 4 times a year);
- systematic euthanasia of stray dogs;
- prevent dogs from feeding on infected sheep carcasses;
- to be careful in human-dog contact (licking, stroking, etc.);
- improvement of hygienic conditions during slaughtering of livestock (including proper destruction of infected by-products);
- vaccination of sheep with a recombinant antigenE. granulosus (EG95) offer encouraging prospects for control. The vaccine is currently in commercial production and licensed in China and Argentina. Trials in Argentina have demonstrated the added value of vaccinating sheep, and the vaccine is widely used in China.
At the individual level
- Do not consume food or water contaminated with dog feces.
- Wash hands with soap and warm water after handling dogs and before eating.