Elaeophora poeli
Encyclopedia
Elaeophora poeli is a parasitic nematode
found in the aorta, and sometimes the heart, of various cattle throughout Asia, and in parts of Africa. It is a large nematode, with males measuring 45-70 mm long and 200-260 µm wide, and females 40-300 mm long and 350 µm wide. Microfilariae are 340-346 µm long and 7.0-7.5 µm wide. Despite the fact that it lives in nodules (aneurysm
s) in the walls of the aorta
and heart
, apparent clinical symptoms of E. poeli infestation are seldom reported.
in 1879, and named Filaria poeli. In 1912, it was transferred to the newly erected genus Elaeophora Railliet and Henry 1912. In 1938, a detailed redescription of E. poeli was published. In that study, E. poeli was determined to be the same animal that previous authors had referred to as Filaria blini and Filaria haemophila, both isolated from Water buffalo
aortas.
(Syncerus caffer), Carabao
or Water buffalo
(Bubalus bubalus), and Zebu
(Bos primigenius indicus). The geographic distribution of this species includes several Asian and African nations: Democratic Republic of Congo, India
, Indonesia
, Malaysia, Mozambique
, the Philippines
, Tanzania
, Thailand
, Uganda
, and Vietnam
.
. They make aneurysm
al (ie. bulging) nodules in the wall of the aorta, which can be up to 2 cm in diameter. The male lives curled up inside the nodule, while the female lives with its head in the nodule and its body free in the lumen
(interior space) of the aorta. Presumably the female sheds the offspring (microfilaria
e) directly into the host's bloodstream. Adults have also been found in nodules on the epicardium
of the heart.
(Bos primigenius indicus) to over 60% in Philippine Bubalus bubalis. A study of free-ranging buffalo in Queen Elizabeth National Park, Uganda, yielded a 55% infestation rate.
s - bulges in the aorta wall - which could conceivably rupture. Corrugated and migratory tract lesions on the inner wall of the aorta and fibrin strands attached to the nodules have also been described. The latter study found narrowing of the aorta down to 1/3 of its usual diameter in some cases.
Despite the presence of nodules 2-cm in diameter on aorta walls and heart tissue, and narrowing of the aorta, almost all studies of E. poeli infestation mention a lack of obvious clinical symptoms in infested individuals. One study found a strong correlation between infestation and visceral pleuresy (inflammation of the membrane that surrounds the lungs).
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...
found in the aorta, and sometimes the heart, of various cattle throughout Asia, and in parts of Africa. It is a large nematode, with males measuring 45-70 mm long and 200-260 µm wide, and females 40-300 mm long and 350 µm wide. Microfilariae are 340-346 µm long and 7.0-7.5 µm wide. Despite the fact that it lives in nodules (aneurysm
Aneurysm
An aneurysm or aneurism is a localized, blood-filled balloon-like bulge in the wall of a blood vessel. Aneurysms can commonly occur in arteries at the base of the brain and an aortic aneurysm occurs in the main artery carrying blood from the left ventricle of the heart...
s) in the walls of the aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
and heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
, apparent clinical symptoms of E. poeli infestation are seldom reported.
Discovery and nomenclature
This species was first described from Water buffaloWater buffalo
The water buffalo is a domesticated bovid widely kept in Asia, Europe and South America.Water buffalo can also refer to:*Wild water buffalo , the wild ancestor of the domestic water buffalo...
in 1879, and named Filaria poeli. In 1912, it was transferred to the newly erected genus Elaeophora Railliet and Henry 1912. In 1938, a detailed redescription of E. poeli was published. In that study, E. poeli was determined to be the same animal that previous authors had referred to as Filaria blini and Filaria haemophila, both isolated from Water buffalo
Water buffalo
The water buffalo is a domesticated bovid widely kept in Asia, Europe and South America.Water buffalo can also refer to:*Wild water buffalo , the wild ancestor of the domestic water buffalo...
aortas.
Hosts and geographic distribution
E. poeli has been found in several species of cattle: African buffaloAfrican Buffalo
The African buffalo, affalo, nyati, Mbogo or Cape buffalo is a large African bovine. It is not closely related to the slightly larger wild Asian water buffalo, but its ancestry remains unclear...
(Syncerus caffer), Carabao
Carabao
The carabao or Bubalus bubalis carabanesis is a subspecies of the domesticated water buffalo found in the Philippines, Guam, Indonesia, Malaysia, and various parts of Southeast Asia...
or Water buffalo
Water buffalo
The water buffalo is a domesticated bovid widely kept in Asia, Europe and South America.Water buffalo can also refer to:*Wild water buffalo , the wild ancestor of the domestic water buffalo...
(Bubalus bubalus), and Zebu
Zebu
Zebu , sometimes known as humped cattle, indicus cattle, Cebu or Brahmin cattle are a type of domestic cattle originating in South Asia, particularly the Indian subcontinent. They are characterised by a fatty hump on their shoulders, drooping ears and a large dewlap...
(Bos primigenius indicus). The geographic distribution of this species includes several Asian and African nations: Democratic Republic of Congo, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, Malaysia, Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
, the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
, Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, Uganda
Uganda
Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...
, and Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
.
Life cycle
The life cycle of E. poeli is not known. The adults usually live attached to the inner walls of the aortaAorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
. They make aneurysm
Aneurysm
An aneurysm or aneurism is a localized, blood-filled balloon-like bulge in the wall of a blood vessel. Aneurysms can commonly occur in arteries at the base of the brain and an aortic aneurysm occurs in the main artery carrying blood from the left ventricle of the heart...
al (ie. bulging) nodules in the wall of the aorta, which can be up to 2 cm in diameter. The male lives curled up inside the nodule, while the female lives with its head in the nodule and its body free in the lumen
Lumen (anatomy)
A lumen in biology is the inside space of a tubular structure, such as an artery or intestine...
(interior space) of the aorta. Presumably the female sheds the offspring (microfilaria
Microfilaria
The microfilaria is a stage in the life cycle of certain parasitic nematodes in the family Onchocercidae. In these species, the adults live in the circulatory system of vertebrates while the early larval stages develop in blood-feeding arthropod vectors...
e) directly into the host's bloodstream. Adults have also been found in nodules on the epicardium
Epicardium
Epicardium describes the outer layer of heart tissue . When considered as a part of the pericardium, it is the inner layer, or visceral pericardium, continuous with the serous layer....
of the heart.
Prevalence
The percentage of animals found to be infested in large-scale slaughterhouse studies range from 1.7% in Tanzanian ZebuZebu
Zebu , sometimes known as humped cattle, indicus cattle, Cebu or Brahmin cattle are a type of domestic cattle originating in South Asia, particularly the Indian subcontinent. They are characterised by a fatty hump on their shoulders, drooping ears and a large dewlap...
(Bos primigenius indicus) to over 60% in Philippine Bubalus bubalis. A study of free-ranging buffalo in Queen Elizabeth National Park, Uganda, yielded a 55% infestation rate.
Clinical significance
The nodules where the filariae reside (as described above) are aneurysmAneurysm
An aneurysm or aneurism is a localized, blood-filled balloon-like bulge in the wall of a blood vessel. Aneurysms can commonly occur in arteries at the base of the brain and an aortic aneurysm occurs in the main artery carrying blood from the left ventricle of the heart...
s - bulges in the aorta wall - which could conceivably rupture. Corrugated and migratory tract lesions on the inner wall of the aorta and fibrin strands attached to the nodules have also been described. The latter study found narrowing of the aorta down to 1/3 of its usual diameter in some cases.
Despite the presence of nodules 2-cm in diameter on aorta walls and heart tissue, and narrowing of the aorta, almost all studies of E. poeli infestation mention a lack of obvious clinical symptoms in infested individuals. One study found a strong correlation between infestation and visceral pleuresy (inflammation of the membrane that surrounds the lungs).