Capillaria aerophila
Encyclopedia
Capillaria aerophila is a nematode
parasite
found in the respiratory tract of fox
es, dog
s, and various other carnivorous mammals. A few cases of human infestation have also been reported. Though it is sometimes called a "lungworm", this term usually refers to other species
of nematodes. Infestation by C. aerophila is referred to as "pulmonary capillariasis" (occasionally spelled "capillariosis), "bronchial capillariasis," or (rarely) "thominxosis." This parasite has a direct life cycle
, meaning that the life cycle can be completed in a single host. C. aerophila usually causes only minor clinical symptoms, such as irritation of the respiratory tract and coughing. However, secondary bacterial infections of the respiratory tract
, including pneumonia
, may develop in heavy infestations. Treatment with anthelmintic
s, such as levamisole
or fenbendazole
, is usually sufficient to cure C. aerophila infestations.
of a wolf, and named Trichosoma aerophila. It was transferred to the genus Eucoleus (as Eucoleus aerophilus) in 1845, and to the genus Capillaria (as Capillaria aerophila) in 1911, and is sometimes referred to as Thominx aerophilum. The changes to the end of the species name in each genus, whether it ends with "-a", "-us" or "-um", are necessary to adhere to the rules of Latin
grammar.
Males generally range from 15-25 mm long, with a maximum width of 62 µm, while females are 18-32 mm long with a maximum width of 105 µm. Some sources report that they are larger when they occur in the nasal sinuses.
, meaning that it can be completed in one host. The adults lay eggs in the lungs. The eggs are coughed up and swallowed by the host; and are then passed in the feces. In about 5-7 weeks, the larvae develop into the infective stage within the egg envelope in the soil. The infective larvae remain viable for up to 1 year. When a suitable host eats these mature eggs, the larvae hatch in the intestines and migrate to the lungs. They mature into adults about 40 days post-infection. Earthworm
s may act as intermediate hosts
, by eating the C. aerophila eggs and infecting mammalian hosts when eaten by the mammals. However, the involvement of the earthworms is not necessary for the completion of the C. aerophila life cycle.
, tracheitis
or bronchitis
), or secondary bacterial infections of the respiratory tract, including bronchopneumonia
. These developments are usually characterized by a whistling sound when the animal breathes, frequent sneezing, or a deep, wheezing cough.
In humans, symptoms include coughing, fever
, bronchitis
, dypsnea (shortness of breath), blood in the saliva, and elevated levels of eosinophils in the blood (eosinophilia
).
Most reports of C. aerophila in wildlife are simply parasite field surveys, and do not mention specific symptoms. However, the involvement of C. aerophila infestation and pneumonia, in addition to other parasites, in the death of an Opossum has been reported.
, are recommended for treatment of dogs. Humans infested with C. aerophila have been successfully treated with albendazole
and mebendazole
.
For animals kept in outdoor pens, proper drainage and allowing sunlight to hit the floor of the pen have been suggested to minimize the spread of infestation.
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
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
found in the respiratory tract of fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...
es, dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
s, and various other carnivorous mammals. A few cases of human infestation have also been reported. Though it is sometimes called a "lungworm", this term usually refers to other species
Lungworm
Lungworms are parasitic nematode worms of the order Strongylida that infest the lungs of vertebrates. The name is used for a variety of different groups of nematodes, some of which also have other common names; what they have in common is that they migrate to their hosts' lungs or respiratory...
of nematodes. Infestation by C. aerophila is referred to as "pulmonary capillariasis" (occasionally spelled "capillariosis), "bronchial capillariasis," or (rarely) "thominxosis." This parasite has a direct life cycle
Parasitic life cycles
Parasite life cycles can take a variety of forms, all involving the exploitation of one or more hosts. Those that must infect more than one host species to complete their life cycles are said to have complex or indirect life cycles, while those that infect a single species have direct life...
, meaning that the life cycle can be completed in a single host. C. aerophila usually causes only minor clinical symptoms, such as irritation of the respiratory tract and coughing. However, secondary bacterial infections of the respiratory tract
Respiratory tract
In humans the respiratory tract is the part of the anatomy involved with the process of respiration.The respiratory tract is divided into 3 segments:*Upper respiratory tract: nose and nasal passages, paranasal sinuses, and throat or pharynx...
, including pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
, may develop in heavy infestations. Treatment with anthelmintic
Anthelmintic
Anthelmintics or antihelminthics are drugs that expel parasitic worms from the body, by either stunning or killing them. They may also be called vermifuges or vermicides .-Pharmaceutical classes:...
s, such as levamisole
Levamisole
Levamisole is an anthelminthic and immunomodulator belonging to a class of synthetic imidazothiazole derivatives. It was discovered at Janssen Pharmaceutica in 1966...
or fenbendazole
Fenbendazole
Fenbendazole is a broad spectrum benzimidazole anthelmintic used against gastrointestinal parasites including roundworms, hookworms, whipworms, the taenia species of tapeworms, pinworms, aelurostrongylus, paragonimiasis, strongyles and strongyloides and can be administered to sheep, cattle,...
, is usually sufficient to cure C. aerophila infestations.
Taxonomy and description
This species was originally described in 1839, from specimens found in the tracheaVertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...
of a wolf, and named Trichosoma aerophila. It was transferred to the genus Eucoleus (as Eucoleus aerophilus) in 1845, and to the genus Capillaria (as Capillaria aerophila) in 1911, and is sometimes referred to as Thominx aerophilum. The changes to the end of the species name in each genus, whether it ends with "-a", "-us" or "-um", are necessary to adhere to the rules of Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
grammar.
Males generally range from 15-25 mm long, with a maximum width of 62 µm, while females are 18-32 mm long with a maximum width of 105 µm. Some sources report that they are larger when they occur in the nasal sinuses.
Hosts and distribution
Capillaria aerophila has been found on every continent, and occurs in dogs, cats, and a wide range of wild mammals. The following species have been reported as hosts:- American MartenAmerican MartenThe American marten is a North American member of the family Mustelidae, sometimes referred to as the pine marten. The name "pine marten" is derived from the common but distinct Eurasian species of Martes...
(Martes americana) in North America - American Black BearAmerican black bearThe American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...
(Ursus americanus) in North America - Arctic FoxArctic foxThe arctic fox , also known as the white fox, polar fox or snow fox, is a small fox native to Arctic regions of the Northern Hemisphere and is common throughout the Arctic tundra biome. The Greek word alopex, means a fox and Vulpes is the Latin version...
(Alopex lagopus) in Iceland - BadgerBadgerBadgers are short-legged omnivores in the weasel family, Mustelidae. There are nine species of badger, in three subfamilies : Melinae , Mellivorinae , and Taxideinae...
(Taxidea taxus) in North America - Beech MartenBeech MartenThe beech marten , also known as the stone marten or white breasted marten, is a species of marten native to much of Europe and Central Asia, though it has established a feral population in North America. It is listed as Least Concern by the IUCN on account of its wide distribution, its large...
(or Stone Marten; Martes foina) in Europe - BobcatBobcatThe bobcat is a North American mammal of the cat family Felidae, appearing during the Irvingtonian stage of around 1.8 million years ago . With twelve recognized subspecies, it ranges from southern Canada to northern Mexico, including most of the continental United States...
(Lynx rufus) in North America - Brown BearBrown BearThe brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...
(Ursus arctos caucasicus) in Russia - CatCatThe cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
(Felis catus) in Asia, Australia, Europe, New Zealand, North America, and South America - CoyoteCoyoteThe coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
(Canis latrans) in North America - Crab-eating FoxCrab-eating FoxThe crab-eating fox , also known as the forest fox, wood fox, and the common fox, is an extant species of medium-sized canid endemic to the central part of South America and which appeared during the Pliocene epoch...
(Cerdocyon thous) in South America - DogDogThe domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...
(Canis lupus familiaris) in Asia, Europe, North America, South America - Egyptian MongooseEgyptian mongooseThe Egyptian Mongoose , also known as the Ichneumon, is a species of mongoose. It may be a reservoir host for Visceral leishmaniasis in Sudan.-Range and habitat:...
(Herpestes ichneumon) in EuropeRepublic of Buryatia| - Eurasian LynxEurasian LynxThe Eurasian lynx is a medium-sized cat native to European and Siberian forests, South Asia and East Asia. It is also known as the European lynx, common lynx, the northern lynx, and the Siberian or Russian lynx...
(Lynx lynx) in Europe - European Pine Marten (Martes martes) in Europe
- European PolecatEuropean polecatThe European polecat , also known as the black or forest polecat , is a species of Mustelid native to western Eurasia and North Africa, which is classed by the IUCN as Least Concern due to its wide range and large numbers. It is of a generally dark brown colour, with a pale underbelly and a dark...
(Mustela putorius) in Europe - Florida pantherFlorida PantherThe Florida panther is an endangered subspecies of cougar that lives in forests and swamps of southern Florida in the United States. Its current taxonomic status is unresolved, but recent genetic research alone does not alter the legal conservation status...
(Puma concolor coryi) in North America - Golden JackalGolden JackalThe golden jackal , also known as the common jackal, Asiatic jackal, thos or gold-wolf is a Canid of the genus Canis indigenous to north and northeastern Africa, southeastern and central Europe , Asia Minor, the Middle East and southeast Asia...
(Canis aureus) in Azerbaijan - Gray FoxGray FoxThe gray fox is a mammal of the order Carnivora ranging throughout most of the southern half of North America from southern Canada to the northern part of South America...
(Urocyon cinereoargenteus) in North America - Gray WolfGray WolfThe gray wolf , also known as the wolf, is the largest extant wild member of the Canidae family...
(Canis lupus) in Europe - HedgehogHedgehogA hedgehog is any of the spiny mammals of the subfamily Erinaceinae and the order Erinaceomorpha. There are 17 species of hedgehog in five genera, found through parts of Europe, Asia, Africa, and New Zealand . There are no hedgehogs native to Australia, and no living species native to the Americas...
(Erinaceus sp.) in Europe, New Zealand - HumanHumanHumans are the only living species in the Homo genus...
(Homo sapiens) only a few cases reported in Europe, Iran and Morocco - Iberian LynxIberian LynxThe Iberian lynx, Lynx pardinus, is a critically endangered species native to the Iberian Peninsula in Southern Europe. It is one of the most endangered cat species in the world. According to the conservation group SOS Lynx, if this species died out, it would be one of the few feline extinctions...
(Lynx pardinus) in Europe - Iriomote CatIriomote catThe Iriomote cat , is a wild cat about the size of a domestic cat that lives exclusively on the Japanese island of Iriomote. It is considered a "living fossil" by many biologists because it has not changed much from its primitive form...
(Prionailurus iriomotensis) in Japan - Japanese Marten (Martes melampus) in Japan
- Kit FoxKit FoxThe kit fox is a fox species of North America. Its range is primarily in the southwestern United States and northern and central Mexico. Some mammalogists classify it as conspecific with the swift fox, V. velox, but molecular systematics imply that the two species are distinct.-Range:The...
(Vulpes macrotis) in North America - Leopard CatLeopard CatThe leopard cat is a small wild cat of South and East Asia. Since 2002 it has been listed as Least Concern by IUCN as it is widely distributed but threatened by habitat loss and hunting in parts of its range...
(Prionailurus bengalensis euptailurus) in Japan - Opossum (Didelphis virginiana) in North America
- RaccoonRaccoonProcyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...
(Procyon lotor) in North America - Raccoon DogRaccoon DogThe raccoon dog , also known as the magnut or tanuki, is a canid indigenous to east Asia. It is the only extant species in the genus Nyctereutes...
(Nyctereutes procyonoides) in Europe and Japan - Red FoxRed FoxThe red fox is the largest of the true foxes, as well as being the most geographically spread member of the Carnivora, being distributed across the entire northern hemisphere from the Arctic Circle to North Africa, Central America, and the steppes of Asia...
(Vulpes vulpes) in Europe and North America - SableSableThe sable is a species of marten which inhabits forest environments, primarily in Russia from the Ural Mountains throughout Siberia, in northern Mongolia and China and on Hokkaidō in Japan. Its range in the wild originally extended through European Russia to Poland and Scandinavia...
(Martes zibellina) in Buryatia (Asia) - WildcatWildcatWildcat is a small felid native to Europe, the western part of Asia, and Africa.-Animals:Wildcat may also refer to members of the genus Lynx:...
(Felis silvestris) in Europe
Life cycle
Capillaria aerophila has a direct life cycleParasitic life cycles
Parasite life cycles can take a variety of forms, all involving the exploitation of one or more hosts. Those that must infect more than one host species to complete their life cycles are said to have complex or indirect life cycles, while those that infect a single species have direct life...
, meaning that it can be completed in one host. The adults lay eggs in the lungs. The eggs are coughed up and swallowed by the host; and are then passed in the feces. In about 5-7 weeks, the larvae develop into the infective stage within the egg envelope in the soil. The infective larvae remain viable for up to 1 year. When a suitable host eats these mature eggs, the larvae hatch in the intestines and migrate to the lungs. They mature into adults about 40 days post-infection. Earthworm
Earthworm
Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...
s may act as intermediate hosts
Parasitic life cycles
Parasite life cycles can take a variety of forms, all involving the exploitation of one or more hosts. Those that must infect more than one host species to complete their life cycles are said to have complex or indirect life cycles, while those that infect a single species have direct life...
, by eating the C. aerophila eggs and infecting mammalian hosts when eaten by the mammals. However, the involvement of the earthworms is not necessary for the completion of the C. aerophila life cycle.
Prevalence
Reported infestation rates in dogs and cats which are kept as pets in Europe and North America are generally less than 10%. In wildlife, rates as high as 74% and 88% have been reported for wild foxes.Clinical symptoms
Most cases of Capillaria aerophila infestation in dogs and cats are without serious clinical symptoms. Heavy infestations may result in inflammation of the respiratory tract (rhinitisRhinitis
Rhinitis , commonly known as a stuffy nose, is the medical term describing irritation and inflammation of some internal areas of the nose. The primary symptom of rhinitis is nasal dripping. It is caused by chronic or acute inflammation of the mucous membrane of the nose due to viruses, bacteria or...
, tracheitis
Tracheitis
Tracheitis is an inflammation of the trachea.Although the trachea is usually considered part of the lower respiratory tract, in ICD-10 tracheitis is classified under "Acute upper respiratory infections".-Bacterial tracheitis:...
or bronchitis
Bronchitis
Acute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...
), or secondary bacterial infections of the respiratory tract, including bronchopneumonia
Bronchopneumonia
Bronchopneumonia or bronchial pneumonia or "Bronchogenic pneumonia" is the acute inflammation of the walls of the bronchioles...
. These developments are usually characterized by a whistling sound when the animal breathes, frequent sneezing, or a deep, wheezing cough.
In humans, symptoms include coughing, fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, bronchitis
Bronchitis
Acute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...
, dypsnea (shortness of breath), blood in the saliva, and elevated levels of eosinophils in the blood (eosinophilia
Eosinophilia
Eosinophilia is a condition in which the eosinophil count in the peripheral blood exceeds 0.45×109/L . A marked increase in non-blood tissue eosinophil count noticed upon histopathologic examination is diagnostic for tissue eosinophilia. Several causes are known, with the most common being...
).
Most reports of C. aerophila in wildlife are simply parasite field surveys, and do not mention specific symptoms. However, the involvement of C. aerophila infestation and pneumonia, in addition to other parasites, in the death of an Opossum has been reported.
Diagnosis, treatment and prevention
Infestation is easily diagnosed by the presence of C. aerophila eggs in the nasal or tracheal lavage, or the feces of infested animals. Standard anthelmintics, such as ivermectin or fenbendazoleFenbendazole
Fenbendazole is a broad spectrum benzimidazole anthelmintic used against gastrointestinal parasites including roundworms, hookworms, whipworms, the taenia species of tapeworms, pinworms, aelurostrongylus, paragonimiasis, strongyles and strongyloides and can be administered to sheep, cattle,...
, are recommended for treatment of dogs. Humans infested with C. aerophila have been successfully treated with albendazole
Albendazole
Albendazole, marketed as Albenza, Eskazole, Zentel and Andazol, is a member of the benzimidazole compounds used as a drug indicated for the treatment of a variety of worm infestations. Although this use is widespread in the United States, the U.S. Food and Drug Administration has not approved...
and mebendazole
Mebendazole
Mebendazole or MBZ is a benzimidazole drug developed by Janssen Pharmaceutica and marketed as Vermox, Ovex, Antiox, and Pripsen...
.
For animals kept in outdoor pens, proper drainage and allowing sunlight to hit the floor of the pen have been suggested to minimize the spread of infestation.
Further reading
- Traversa D., Cesare A. Di & Conboy G. (2010). "Canine and feline cardiopulmonary parasitic nematodes in Europe: emerging and underestimated". Parasites & VectorsParasites & VectorsParasites & Vectors is a peer-reviewed open-access medical journal published by BioMed Central. The journal publishes articles on the biology of parasites, parasitic diseases, intermediate hosts, vectors and vector-borne pathogens. Parasites & Vectors was established in 2008 as a merger of Filaria...
3: 62. doi:10.1186/1756-3305-3-62.