Trichinella britovi
Encyclopedia
Trichinella britovi is a nematode
parasite responsible for a zoonotic disease
called trichinellosis. There are currently eight known species of Trichinella. Only three of the Trichinella species cause trichinellosis, and Trichinella britovi is one of them. Numerous mammal species as well as birds and crocodiles can harbor the parasite worldwide, but the sylvatic cycle
is mainly maintained by wild carnivores.
Humans represent only a possible host
and the parasite is exclusively transmitted through consumption of raw or rare
meat. In Europe, pork
, wild boar meat and horse meat
are the main sources for human infection.
Because of mandatory veterinary controls in slaughterhouse
s, large trichinellosis outbreaks due to horse meat consumption are rare, but cases in hunters and their families after raw or rare wild boar meat consumption are regularly reported, with over one hundred cases since 1975.
T. britovi in wild boar is relatively resistant to freezing. It was observed in France that meat from naturally infected wild boar meat frozen for three weeks at −20 °C remained infectious, whereas they were not viable after four weeks.
In the 1960s, trichinella infection was documented in Senegal
, West Africa
. A survey of 160 wild animals from that region produced plausible evidence that European strains may have originated in Africa. It has also been proposed that strains of Trichella britovi are isolated to both African and European populations.
Thus according to the International Commission on Trichinellosis, meat should be heated at 65 °C (149 °F) for at least 1 minute to kill Trichinella larvae; larvae die when the color of the meat at the core changes from pink to brown.
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
parasite responsible for a zoonotic disease
Zoonosis
A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were zoonotic...
called trichinellosis. There are currently eight known species of Trichinella. Only three of the Trichinella species cause trichinellosis, and Trichinella britovi is one of them. Numerous mammal species as well as birds and crocodiles can harbor the parasite worldwide, but the sylvatic cycle
Sylvatic cycle
The sylvatic cycle, also enzootic or sylvatic transmission cycle, is a portion of the natural transmission cycle of a pathogen. The sylvatic cycle is the fraction of the pathogen population's lifespan spent cycling between wild animals and vectors. Humans are usually an incidental or dead-end host,...
is mainly maintained by wild carnivores.
Humans represent only a possible host
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
and the parasite is exclusively transmitted through consumption of raw or rare
Temperature (meat)
Temperature is a description of how thoroughly cooked a cut of meat is based on the color, juiciness and internal temperature when cooked. The gradations of cooking are most often used in reference to beef but are also applicable to lamb, pork, poultry, veal, and seafood .Gradations, their...
meat. In Europe, pork
Pork
Pork is the culinary name for meat from the domestic pig , which is eaten in many countries. It is one of the most commonly consumed meats worldwide, with evidence of pig husbandry dating back to 5000 BC....
, wild boar meat and horse meat
Horse meat
Horse meat is the culinary name for meat cut from a horse. It is a major meat in only a few countries, notably in Central Asia, but it forms a significant part of the culinary traditions of many others, from Europe to South America to Asia. The top eight countries consume about 4.7 million horses...
are the main sources for human infection.
Because of mandatory veterinary controls in slaughterhouse
Slaughterhouse
A slaughterhouse or abattoir is a facility where animals are killed for consumption as food products.Approximately 45-50% of the animal can be turned into edible products...
s, large trichinellosis outbreaks due to horse meat consumption are rare, but cases in hunters and their families after raw or rare wild boar meat consumption are regularly reported, with over one hundred cases since 1975.
T. britovi in wild boar is relatively resistant to freezing. It was observed in France that meat from naturally infected wild boar meat frozen for three weeks at −20 °C remained infectious, whereas they were not viable after four weeks.
In the 1960s, trichinella infection was documented in Senegal
Senegal
Senegal , officially the Republic of Senegal , is a country in western Africa. It owes its name to the Sénégal River that borders it to the east and north...
, West Africa
West Africa
West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:...
. A survey of 160 wild animals from that region produced plausible evidence that European strains may have originated in Africa. It has also been proposed that strains of Trichella britovi are isolated to both African and European populations.
Prevention
To prevent trichinellosis, an official European directive recommends the freezing of meat at −25 °C for at least 10 days for pieces of meat less than 25 cm (10 in) thickness. Patients froze wild boar steaks at −35 °C for seven days, but this freezing time appears insufficient to kill larvae, since T. britovi is a species relatively resistant to freezing.Thus according to the International Commission on Trichinellosis, meat should be heated at 65 °C (149 °F) for at least 1 minute to kill Trichinella larvae; larvae die when the color of the meat at the core changes from pink to brown.