Elaeophora sagitta
Encyclopedia
Elaeophora sagitta is a parasitic nematode
found in the heart, coronary arteries and pulmonary arteries
of several ruminant
species and Water buffalo
in Africa. Infestation usually occurs without significant health effects in the Greater kudu
(Tragelaphus strepsiceros), but may affect cardiac function in some other host species.
(Tragelaphus scriptus) from Cameroon
, and named Filaria sagitta. In 1926, it was transferred to the genus Cordophilus, as Cordophilus sagittus. In 1976, the genus Cordophilus was made a synonym
of the genus Elaeophora, so this species became Elaeophora sagitta.
s of the lungs of various hosts: Bushbuck
(Tragelaphus scriptus), Greater kudu
(Tragelaphus strepsiceros), bongos
(Tragelaphus eurycerus), nyala
(Tragelaphus angasii), common eland
(Taurotragus oryx), and African Forest Buffalo
(Syncerus caffer nanus). This species has also been found in unspecified "cattle". Lesions similar to those described in E. sagitta infestations were also found in sheep (Ovis aries), but the actual parasites were not recovered. E. sagitta has been found in several African nations: Cameroon
, Kenya
, Malawi
, Mocambique, the Republic of the Congo
, South Africa
and Swaziland
.
, since the female sheds microfilariae, rather than eggs, directly into the blood stream.
. Infestation in a herd of eland
(Taurotragus oryx) in Kruger National Park was reported as "nearly half of 33" individuals. A slaughterhouse survey in Swaziland yielded a very low prevalence–77 of 18,458 (0.416%) -- of bovine hearts showing lesions typical of E. sagitta infestation. In other host species, only isolated cases have been reported.
, as well as coronary
and pulmonary
arteries, and occasionally coronary veins. They produce aneurysm
al (bulging) lesions in the vessel walls which are 1–2 cm in diameter, and have been associated with hypertrophy
and dilatation of heart ventricles, thrombosis
(blood clots) and myocarditis
(inflammation of the heart muscle). The degree of interference with general circulatory function has not been studied in detail. As one author points out, however, if the infested host is fleeing from a lion, only a minor difference in cardiopulmonary efficiency could certainly affect survival.
E. sagitta infestation appears to be clinically benign
in greater kudu
. Some fatalities in a herd of eland
were attributed to E. sagitta infestation, though many of the eland were also "heavily" infested with various gastrointestinal parasites. In the Congo, E. sagitta infestation was suggested to be one of the factors which led to mortality in several bongos
(Tragelaphus eurycerus) and one African Forest Buffalo
(Syncerus caffer nanus)
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 heart, coronary arteries and pulmonary arteries
Pulmonary artery
The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
of several ruminant
Ruminant
A ruminant is a mammal of the order Artiodactyla that digests plant-based food by initially softening it within the animal's first compartment of the stomach, principally through bacterial actions, then regurgitating the semi-digested mass, now known as cud, and chewing it again...
species and 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...
in Africa. Infestation usually occurs without significant health effects in the Greater kudu
Greater Kudu
The Greater Kudu is a woodland antelope found throughout eastern and southern Africa. Despite occupying such widespread territory, they are sparsely populated in most areas, due to a declining habitat, deforestation and hunting....
(Tragelaphus strepsiceros), but may affect cardiac function in some other host species.
Discovery and nomenclature
This species was first described in 1907 from the heart of a BushbuckBushbuck
The bushbuck is the most widespread antelope in Sub-Saharan Africa, and is found in rain forests, montane forests, forest-savanna mosaics and bush savannaforest and woodland. Recently, genetic studies have shown that the bushbuck, is in fact a complex of two geographically and phenotypically...
(Tragelaphus scriptus) from Cameroon
Cameroon
Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...
, and named Filaria sagitta. In 1926, it was transferred to the genus Cordophilus, as Cordophilus sagittus. In 1976, the genus Cordophilus was made a synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
of the genus Elaeophora, so this species became Elaeophora sagitta.
Hosts and geographic distribution
Adults of E. sagitta have been found attached to the inner walls of the chambers and vessels of the heart, as well as the arterioleArteriole
An arteriole is a small diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries.Arterioles have muscular walls and are the primary site of vascular resistance...
s of the lungs of various hosts: Bushbuck
Bushbuck
The bushbuck is the most widespread antelope in Sub-Saharan Africa, and is found in rain forests, montane forests, forest-savanna mosaics and bush savannaforest and woodland. Recently, genetic studies have shown that the bushbuck, is in fact a complex of two geographically and phenotypically...
(Tragelaphus scriptus), Greater kudu
Greater Kudu
The Greater Kudu is a woodland antelope found throughout eastern and southern Africa. Despite occupying such widespread territory, they are sparsely populated in most areas, due to a declining habitat, deforestation and hunting....
(Tragelaphus strepsiceros), bongos
Bongo (antelope)
The western or lowland bongo, Tragelaphus eurycerus eurycerus, is a herbivorous, mostly nocturnal forest ungulate and among the largest of the African forest antelope species....
(Tragelaphus eurycerus), nyala
Nyala
The Nyala is a Southern African antelope. It is a spiral-horned dense-forest antelope that is uncomfortable in open spaces and is most often seen at water holes. Nyalas live alone or in small family groups of up to 10 individuals.The male stands up to 110 cm , the female is up to 90 cm ...
(Tragelaphus angasii), common eland
Common Eland
The common eland , also known as the southern eland or eland antelope, is a savannah and plains antelope found in East and Southern Africa. It is the largest antelope in the African continent...
(Taurotragus oryx), and African Forest Buffalo
African Forest Buffalo
The African Forest Buffalo is smaller than the Cape Buffalo, with horns that curves out backwards and upwards. Usually weighing , they are reddish brown in color. Its native habitat is the equatorial forest found in central and western Africa, and its diet consists primarily of grasses, twigs, and...
(Syncerus caffer nanus). This species has also been found in unspecified "cattle". Lesions similar to those described in E. sagitta infestations were also found in sheep (Ovis aries), but the actual parasites were not recovered. E. sagitta has been found in several African nations: Cameroon
Cameroon
Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...
, Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
, Malawi
Malawi
The Republic of Malawi is a landlocked country in southeast Africa that was formerly known as Nyasaland. It is bordered by Zambia to the northwest, Tanzania to the northeast, and Mozambique on the east, south and west. The country is separated from Tanzania and Mozambique by Lake Malawi. Its size...
, Mocambique, the Republic of the Congo
Republic of the Congo
The Republic of the Congo , sometimes known locally as Congo-Brazzaville, is a state in Central Africa. It is bordered by Gabon, Cameroon, the Central African Republic, the Democratic Republic of the Congo , the Angolan exclave province of Cabinda, and the Gulf of Guinea.The region was dominated by...
, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
and Swaziland
Swaziland
Swaziland, officially the Kingdom of Swaziland , and sometimes called Ngwane or Swatini, is a landlocked country in Southern Africa, bordered to the north, south and west by South Africa, and to the east by Mozambique...
.
Life cycle
The life cycle of E. sagitta has not been studied in detail. It is viviparousVivipary
Vivipary has two different meanings. In animals, it means development of the embryo inside the body of the mother, eventually leading to live birth, as opposed to laying eggs...
, since the female sheds microfilariae, rather than eggs, directly into the blood stream.
Prevalence
Infestation rates as high as 74% and over 90% have been reported in free-ranging kuduKudu
The kudus are two species of antelope of the genus Tragelaphus:*Lesser Kudu, Tragelaphus imberbis*Greater Kudu, Tragelaphus strepsiceros- Etymology :...
. Infestation in a herd of eland
Common Eland
The common eland , also known as the southern eland or eland antelope, is a savannah and plains antelope found in East and Southern Africa. It is the largest antelope in the African continent...
(Taurotragus oryx) in Kruger National Park was reported as "nearly half of 33" individuals. A slaughterhouse survey in Swaziland yielded a very low prevalence–77 of 18,458 (0.416%) -- of bovine hearts showing lesions typical of E. sagitta infestation. In other host species, only isolated cases have been reported.
Clinical significance
E. sagitta adults are typically found in the heart ventriclesVentricle (heart)
In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. The Atria primes the Pump...
, as well as coronary
Coronary circulation
Coronary circulation is the circulation of blood in the blood vessels of the heart muscle . The vessels that deliver oxygen-rich blood to the myocardium are known as coronary arteries...
and pulmonary
Pulmonary artery
The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
arteries, and occasionally coronary veins. They produce 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 (bulging) lesions in the vessel walls which are 1–2 cm in diameter, and have been associated with hypertrophy
Hypertrophy
Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It should be distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number...
and dilatation of heart ventricles, thrombosis
Thrombosis
Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...
(blood clots) and myocarditis
Myocarditis
Myocarditis is inflammation of heart muscle . It resembles a heart attack but coronary arteries are not blocked.Myocarditis is most often due to infection by common viruses, such as parvovirus B19, less commonly non-viral pathogens such as Borrelia burgdorferi or Trypanosoma cruzi, or as a...
(inflammation of the heart muscle). The degree of interference with general circulatory function has not been studied in detail. As one author points out, however, if the infested host is fleeing from a lion, only a minor difference in cardiopulmonary efficiency could certainly affect survival.
E. sagitta infestation appears to be clinically benign
Benignity
Benignity [from Latin benignus , from bonus + genus ] is a medical term used to describe a condition that is harmless...
in greater kudu
Greater Kudu
The Greater Kudu is a woodland antelope found throughout eastern and southern Africa. Despite occupying such widespread territory, they are sparsely populated in most areas, due to a declining habitat, deforestation and hunting....
. Some fatalities in a herd of eland
Common Eland
The common eland , also known as the southern eland or eland antelope, is a savannah and plains antelope found in East and Southern Africa. It is the largest antelope in the African continent...
were attributed to E. sagitta infestation, though many of the eland were also "heavily" infested with various gastrointestinal parasites. In the Congo, E. sagitta infestation was suggested to be one of the factors which led to mortality in several bongos
Bongo (antelope)
The western or lowland bongo, Tragelaphus eurycerus eurycerus, is a herbivorous, mostly nocturnal forest ungulate and among the largest of the African forest antelope species....
(Tragelaphus eurycerus) and one African Forest Buffalo
African Forest Buffalo
The African Forest Buffalo is smaller than the Cape Buffalo, with horns that curves out backwards and upwards. Usually weighing , they are reddish brown in color. Its native habitat is the equatorial forest found in central and western Africa, and its diet consists primarily of grasses, twigs, and...
(Syncerus caffer nanus)