Acanthocheilonemiasis | |
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Specialty | Infectious diseases |
Acanthocheilonemiasis is a rare tropical infectious disease caused by a parasite known as Acanthocheilonema perstans . It can cause skin rashes, abdominal and chest pains, muscle and joint pains, neurological disorders and skin lumps. It is mainly found in Africa. The parasite is transmitted through the bite of small flies. Studies show that there are elevated levels of white blood cells.
Acanthocheilonemiasis belongs to a group of parasitic diseases known as filarial disease (nematode), all of which are classified as Neglected Tropical Diseases. [1] [2] Filarial disease results when microfilariae, which are nematode larvae, reach the lymphatic system; microfilariae reside in the serous cavities of humans. They have a five-stage life cycle that includes birth to thousands of live microfilariae within the host (i.e. human body), and then translocation via blood meal to the dermis layer of the skin. It is here that microfilariae cause major symptoms, which are edema and thickening of the skin and underlying connective tissues. It can also cause skin rashes, abdominal and chest pains, muscle (myalgia) and joint pains, neurological disorders and skin lumps. In addition, it causes spleen and liver enlargement, which is called hepatosplenomegaly. Studies show elevated levels of leukocytes, or white blood cells, which is referred to as eosinophilia. It is mainly found in Africa. The parasite is transmitted through the bite of small flies (A. coliroides). [1] [3]
Generally speaking, acanthocheilonemiasis does not show initial symptoms. However, if symptoms do arise, it is typically in individuals who are visiting highly infected areas rather than natives to those areas. A major common laboratory finding is an increase in specialized white blood cells, which is called eosinophilia. [3]
Other symptoms include itchy skin, neurological symptoms, abdominal and chest pain, muscle pain, and swelling underneath the skin. If there are abnormally high levels of white blood cells, then a physical examination will most likely find an enlarged spleen or liver. [3]
In certain scenarios, nematodes may physically lodge into the chest or abdomen, resulting in an inflammation. Diagnosis of this condition usually occurs via a blood smear examination under light microscopy. [3]
Absolute eosinophilia in immigrants that is correlated with parasitic diseases that may go undiagnosed. Absolute eosinophilia is clinically diagnosed as >0.45×109 eosinophilic leucocytes/L of peripheral blood. [4] Recent studies suggest that around 60% of children with relative eosinophilia contracted this via parasitic infections. Relative eosinophilia is different from absolute because relative refers to an increase in percentage of white blood cells (i.e. leukocytes) due to a loss of blood plasma; where as absolute eosinophilia is purely an increase in white blood cell production. [5] Of those with relative eosinophilia, 40% were undiagnosed until these studies. [4] Therefore, there is a great need for thorough parasitological studies in this area of tropical infectious diseases. [4]
The standard of care is administration of antifilarial drugs, most commonly Ivermectin or diethyl-carbamazine (DEC). The most efficacious dose in all nematode and parasitic infections is 200 μg/kg of ivermectin. [6] There has also been other various anthelminthic drugs used, such as mebendazole, levamisole, albendazole and thiabendazole. [2] [7] In worst-case scenarios, surgery may be necessary to remove nematodes from the abdomen or chest. However, mild cases usually do not require treatment. [3]
Acanthocheilonemiasis is caused by the parasite, mansonella perstans.M. perstans is primarily found in central Africa and in some areas of South America, therefore the most affected populations are located in these areas. Acanthocheilonemiasis affects humans in these areas in equal numbers. [3] The prevalence of this condition does significantly increase with age. [8] Furthermore, the parasite is most commonly found in areas of tropical forests with alternating swamps and open ground. [8]
Approximately 114 million people in Africa are infected with M. perstans, including 33 sub-Saharan African countries. Recent studies focused on Gabon specifically, where febrile and tropical diseases are common. [2] [8] Contrary to popular recent suggestions, M. perstans does not influence the emergence of febrile diseases, including HIV, tuberculosis, bacteremia, and malaria. [2] In general, hemoglobin levels in individuals with malaria are severely reduced from that of a healthy individual. Reduced levels occur because the malaria parasite, Plasmodium falciparum, utilizes human hemoglobin as its major energy source. [9] Filariasis, in combination with severe malaria, actually shows higher hemoglobin levels than in severe malaria alone. [8] [10] In addition, M. perstans did not have adverse effects on those with HIV, as there were actually higher levels of CD4 in HIV patients co-infected with M. perstans. [8] [11]
Tropical and sub-tropical regions are the main areas affected by nematodes and parasitic worms, which often causes filariasis. [3] Around 20% of immigrants to Spain are children from these regions. [4]
The clinical manifestations of A. perstans were first discovered in London in the blood of a patient from West Africa in 1890. The parasite was originally called Filaria sanguinis hominis minor because it was similar to another microfilariae, except smaller. Microfilariae are small larvae that have the ability to enter the body's circulation. Filaria sanguinis hominis minor is now called Filaria perstans, which was established by the International Commission on Zoological Nomenclature. [2]
Since its discovery, Acanthocheilonemiasis has had several other names. It was first known as mansonelliasis, which referred to an infectious disease of any of three parasite species, including ozzardi, perstans, and streptocerca that share similar life cycle characteristics. However, it is now widely accepted as M. perstans. [2] Other synonyms for acanthocheilonemiasis include: Dipetalonemiasis, Dipetalonema perstans, Mansonalla perstans, and Acanthocheilonemiasis perstans. [12]
Parasitic worms and nematodes regulate many immune pathways of their host in order to increase their chances of survival. [13] For example, molecules secreted by Acanthocheilonema vitae actually limit host effective immune mechanisms. These molecules are called excretory-secretory products. An effective excretory-secretory product released from Acanthochelionema vitae is called ES-62, which can affect multiple immune system cell types. ES-62 has anti-inflammatory effects when subjected to mice. [13] The anti-inflammatory effect occurs because of a phosphorylcholine (PC)-containing moiety and signal transduction. More research needs to be completed; however there is some evidence that Acanthocheilonema vitae may have anti-inflammatory effects, and should be researched further. [13]
Loa loa is a filarial (arthropod-borne) nematode (roundworm) that causes Loa loa filariasis. Loa loa actually means "worm worm", but is commonly known as the "eye worm", as it localizes to the conjunctiva of the eye. Loa loa is commonly found in Africa. It mainly inhabits rain forests in West Africa and has native origins in Ethiopia. The disease caused by Loa loa is called loiasis and is one of the neglected tropical diseases.
Onchocerciasis, also known as river blindness, is a disease caused by infection with the parasitic worm Onchocerca volvulus. Symptoms include severe itching, bumps under the skin, and blindness. It is the second-most common cause of blindness due to infection, after trachoma.
Filariasis, is a filarial infection caused by parasitic nematodes (roundworms) spread by different vectors. They are included in the list of neglected tropical diseases.
Wuchereria bancrofti is a filarial (arthropod-borne) nematode (roundworm) that is the major cause of lymphatic filariasis. It is one of the three parasitic worms, together with Brugia malayi and B. timori, that infect the lymphatic system to cause lymphatic filariasis. These filarial worms are spread by a variety of mosquito vector species. W. bancrofti is the most prevalent of the three and affects over 120 million people, primarily in Central Africa and the Nile delta, South and Central America, the tropical regions of Asia including southern China, and the Pacific islands. If left untreated, the infection can develop into lymphatic filariasis. In rare conditions, it also causes tropical pulmonary eosinophilia. No vaccine is commercially available, but high rates of cure have been achieved with various antifilarial regimens, and lymphatic filariasis is the target of the World Health Organization Global Program to Eliminate Lymphatic Filariasis with the aim to eradicate the disease as a public-health problem by 2020. However, this goal was not met by 2020.
Helminthiasis, also known as worm infection, is any macroparasitic disease of humans and other animals in which a part of the body is infected with parasitic worms, known as helminths. There are numerous species of these parasites, which are broadly classified into tapeworms, flukes, and roundworms. They often live in the gastrointestinal tract of their hosts, but they may also burrow into other organs, where they induce physiological damage.
Tropical medicine is an interdisciplinary branch of medicine that deals with health issues that occur uniquely, are more widespread, or are more difficult to control in tropical and subtropical regions.
Brugia malayi is a filarial (arthropod-borne) nematode (roundworm), one of the three causative agents of lymphatic filariasis in humans. Lymphatic filariasis, also known as elephantiasis, is a condition characterized by swelling of the lower limbs. The two other filarial causes of lymphatic filariasis are Wuchereria bancrofti and Brugia timori, which both differ from B. malayi morphologically, symptomatically, and in geographical extent.
Onchocerca volvulus is a filarial (arthropod-borne) nematode (roundworm) that causes onchocerciasis, and is the second-leading cause of blindness due to infection worldwide after trachoma. It is one of the 20 neglected tropical diseases listed by the World Health Organization, with elimination from certain countries expected by 2025.
Acanthocheilonema is a genus within the family Onchocercidae which comprises mainly tropical parasitic worms. Cobbold created the genus Acanthocheilonema with only one species, Acanthocheilonema dracunculoides, which was collected from aardwolf in the region of South Africa in the nineteenth century. These parasites have a wide range of mammalian species as hosts, including members of Carnivora, Macroscelidea, Rodentia, Pholidota, Edentata, and Marsupialia. Many species among several genera of filarioids exhibit a high degree of endemicity in studies done on mammalian species in Japan. However, no concrete evidence has confirmed any endemic species in the genus Acanthocheilonema.
Lymphatic filariasis is a human disease caused by parasitic worms known as filarial worms. Usually acquired in childhood, it is a leading cause of permanent disability worldwide, impacting over a hundred million people and manifesting itself in a variety of severe clinical pathologies While most cases have no symptoms, some people develop a syndrome called elephantiasis, which is marked by severe swelling in the arms, legs, breasts, or genitals. The skin may become thicker as well, and the condition may become painful. Affected people are often unable to work and are often shunned or rejected by others because of their disfigurement and disability.
Mansonella perstans is a filarial (arthropod-borne) nematode (roundworm), transmitted by tiny blood-sucking flies called midges. Mansonella perstans is one of two filarial nematodes that causes serous cavity filariasis in humans. The other filarial nematode is Mansonella ozzardi. M. perstans is widespread in many parts of sub-Saharan Africa, parts of Central and South America, and the Caribbean.
Mansonelliasis is the condition of infection by the nematode Mansonella. The disease exists in Africa and tropical Americas, spread by biting midges or blackflies. It is usually asymptomatic.
Brugia timori is a filarial (arthropod-borne) nematode (roundworm) which causes the disease "Timor filariasis", or "Timorian filariasis". While this disease was first described in 1965, the identity of Brugia timori as the causative agent was not known until 1977. In that same year, Anopheles barbirostris was shown to be its primary vector. There is no known animal reservoir host.
The Onchocercidae are a family of nematodes in the superfamily Filarioidea. This family includes some of the most devastating human parasitic diseases, such as lymphatic filariasis, onchocerciasis, loiasis, and other filariases.
Mansonella ozzardi is a filarial (arthropod-borne) nematode (roundworm). This filarial nematode is one of two that causes serous cavity filariasis in humans. The other filarial nematode that causes it in humans is Mansonella perstans. M. ozzardi is an endoparasite that inhabits the serous cavity of the abdomen in the human host. It lives within the mesenteries, peritoneum, and in the subcutaneous tissue.
The Filarioidea are a superfamily of highly specialised parasitic nematodes. Species within this superfamily are known as filarial worms or filariae. Infections with parasitic filarial worms cause disease conditions generically known as filariasis. Drugs against these worms are known as filaricides.
Mansonella streptocerca,, is a filarial (arthropod-borne) nematode (roundworm) causing the disease streptocerciasis. It is a common parasite in the skin of humans in the rain forests of Africa, where it is thought to be a parasite of chimpanzees, as well.
Mansonella is a genus of parasitic nematodes. It includes three species that are responsible for the disease mansonelliasis: Mansonella ozzardi, M. perstans, and M. streptocerca. A potential fourth species has been identified in Gabon in 2015 and proposed as a new species Mansonella sp. "DEUX". Whole-genome sequences from Mansonella perstans, Mansonella ozzardi, and the newly proposed species Mansonella sp. "DEUX" have been assembled.
Tropical pulmonary eosinophilia, is characterized by cough, bronchospasm, wheezing, abdominal pain, and an enlarged spleen. Occurring most frequently in the Indian subcontinent and Southeast Asia, TPE is a clinical manifestation of lymphatic filariasis, a parasitic infection caused by filarial roundworms that inhabit the lymphatic vessels, lymph nodes, spleen, and bloodstream. Three species of filarial roundworms, all from the Onchocercidae family, cause human lymphatic filariasis: Wuchereria bancrofti, Brugia malayi, and Brugia timori.
Eosinophilic myocarditis is inflammation in the heart muscle that is caused by the infiltration and destructive activity of a type of white blood cell, the eosinophil. Typically, the disorder is associated with hypereosinophilia, i.e. an eosinophil blood cell count greater than 1,500 per microliter. It is distinguished from non-eosinophilic myocarditis, which is heart inflammation caused by other types of white blood cells, i.e. lymphocytes and monocytes, as well as the respective descendants of these cells, NK cells and macrophages. This distinction is important because the eosinophil-based disorder is due to a particular set of underlying diseases and its preferred treatments differ from those for non-eosinophilic myocarditis.