| Pterygodermatites peromysci | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Chromadorea |
| Order: | Rhabditida |
| Family: | Rictulariidae |
| Genus: | Pterygodermatites |
| Species: | P. peromysci |
| Binomial name | |
| Pterygodermatites peromysci Lichtenfels, 1970 | |
Pterygodermatites peromysci is an intestinal parasitic nematode [1] in the genus Pterygodermatites of the family Rictulariidae.
Scanning electron microscopy (SEM) studies of Pterygodermatites peromysci have not been conducted yet, but might provide scientists with an understanding about how it causes pathology in the gastrointestinal tract of the host, as worms have been found in vitro as large as 38 mm in a host mouse with a body length size of 90 mm. In a case where 8 of these adult worms were discovered in a mouse, it was noted that the mouse had a very inflamed and damaged gut from the internal damage of pressure on host tissues (1). However, scanning electron microscopy studies have been conducted on Pterygodermatites bovieri in which the definitive host is bats (2) and on Pterygodermatites mesopectines which has been noted to parasitize a commensal rodent, Mastomys natalensis (3) so a comparison SEM study of the morphology of the head of P. peromysci with previously SEM studied species may present interesting results since SEM studies of the Pterygodermatites species which infects a rodent (Mastomys natalensis) has already been worked out.
Though a scanning electron microscopy study of P. peromysci hasn’t been worked out, there do exist stereo microscope images of the morphology of the egg with a hatching third stage infectious juvenile which infect white-footed mice, Peromyscus leucopus, (Figure 2, source 4). Parasitic infection of the definitive mouse occurs once the encysted egg in the haemocoel of the intermediate host, a camel cricket, is ingested via mouse-based predation of the intermediate host. To complete this life cycle characteristic of nematodes in the family Rictulariidae, P. peromysci larvae migrates into the gastrointestinal tract, molting into a 4th stage juvenile and then into an adult. The life cycle is continued when the mouse sheds its embryonated eggs into the environment (Figure 1, source 4). What is notable about this life-cycle is that the eggs are embryonated, rather than non-embryonated, when they are passed into the environment. Since the intermediate host is most abundant during the months of August – September, the prevalence of infection in these mice is greatest during the end of the summer months. Furthermore, the eggs are able to survive the winter, hatch in the spring, and then continue the infection cycle with the camel crickets (4). However though P. peromysci has been more commonly observed in white-footed mice (Peromyscus leucopus), it has also been reported identified using flying squirrels as its definitive host such as the northern flying squirrel (Glaucomys sabrinus) and the southern flying squirrel (Glaucomys volans) which illustrates that there is more than one possible definitive host for P. peromysci (5).
Pterygodermatites peromysci has been discovered in Florida and in Pennsylvania primarily in white-footed mice (Peromyscus leucopus). [2] Geographically the infected mice have been shown to be abundant in flatwood habitats of Florida, characterized by poorly draining soils which may have standing water during rainy seasons. Here, the vegetation is usually rather diverse. In other places infected mice have been identified in the hardwood forests of Pennsylvania (3, 6). Further complicating the life-cycle, but still with regard to geographical distribution, P. peromysci adults have been identified in New York as well as in Pennsylvania in flying squirrel populations. In the flying squirrel hosts, another parasite, Strongyloides robustus was also identified. The scientists hypothesized that perhaps initial infection with S. robustus via skin penetration of the flying squirrel host might alter the immune response of the host in such a way that encourages co-infection of the gastrointestinal tract with P. peromysci (5). Furthermore, in the flying squirrels, the pathology was not deemed severe from spleen masses collected from the squirrels as the spleens were not appreciably enlarged from pathology. Perhaps the reduced pathology in this case is due to parasitic competition between S. robustus and P. peromysci as S. robustus takes most of the chemical resources from P. peromysci as S. robustus was most abundant in all the specimens co-infected with the two parasites.
Perhaps since the life-cycle of P. peromysci in its definitive host involves predation of crickets, parasitism in humans is not a predominant problem in countries such as the United States where consumption of insects is not a common-practice (4). This may explain why the Center for Disease Control (CDC) has not published any online reports on human infection by P. peromysci. While this may not prove that it definitely has never infected humans, it may explain the current absence of observed zoonosis findings or the need for human treatment.
In a field study to determine if there was sex-biased infection towards male mice, female and male mice were separated into groups and administered an antihelminthic drug to clear the infection of P. peromysci adults in infected rodents to test if males or females released more infectious eggs ingested by cricket intermediate hosts. The antihelminthic drug was levamisole hydrochloride which when tested in the infected mice was shown to be able to control and prevent infection of P. peromysci in both the male and female mice for up to 2 weeks optimally, but no longer than 4 weeks for the dose given (7). Probably after 2 weeks of the treatment dose (36 mg / kg) the free mice were susceptible to reinfection.
Trematoda is a class of flatworms known as flukes or trematodes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive host, where the flukes sexually reproduce, is a vertebrate. Infection by trematodes can cause disease in all five traditional vertebrate classes: mammals, birds, amphibians, reptiles, and fish.
Hymenolepiasis is infestation by one of two species of tapeworm: Hymenolepis nana or H. diminuta. Alternative names are dwarf tapeworm infection and rat tapeworm infection. The disease is a type of helminthiasis which is classified as a neglected tropical disease.
Fasciola hepatica, also known as the common liver fluke or sheep liver fluke, is a parasitic trematode of the class Trematoda, phylum Platyhelminthes. It infects the livers of various mammals, including humans, and is transmitted by sheep and cattle to humans all over the world. The disease caused by the fluke is called fasciolosis or fascioliasis, which is a type of helminthiasis and has been classified as a neglected tropical disease. Fasciolosis is currently classified as a plant/food-borne trematode infection, often acquired through eating the parasite's metacercariae encysted on plants. F. hepatica, which is distributed worldwide, has been known as an important parasite of sheep and cattle for decades and causes significant economic losses in these livestock species, up to £23 million in the UK alone. Because of its relatively large size and economic importance, it has been the subject of many scientific investigations and may be the best-known of any trematode species. F. hepatica's closest relative is Fasciola gigantica. These two flukes are sister species; they share many morphological features and can mate with each other.
Trematodes are parasitic flatworms of the class Trematoda, specifically parasitic flukes with two suckers: one ventral and the other oral. Trematodes are covered by a tegument, that protects the organism from the environment by providing secretory and absorptive functions.
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Echinostoma is a genus of trematodes (flukes), which can infect both humans and other animals. These intestinal flukes have a three-host life cycle with snails or other aquatic organisms as intermediate hosts, and a variety of animals, including humans, as their definitive hosts.
The white-footed mouse is a rodent native to North America from Ontario, Quebec, Labrador, and the Maritime Provinces to the southwestern United States and Mexico. In the Maritimes, its only location is a disjunct population in southern Nova Scotia. It is also known as the woodmouse, particularly in Texas.
Spirometra erinaceieuropaei is a parasitic tapeworm that infects domestic animals and humans. The medical term for this infection in humans and other animals is sparganosis. Morphologically, these worms are similar to other worms in the genus Spirometra. They have a long body consisting of three sections: the scolex, the neck, and the strobilia. They have a complex life cycle that consists of three hosts, and can live in varying environments and bodily tissues. Humans can contract this parasite in three main ways. Historically, humans are considered a paratenic host; however, the first case of an adult S. erinaceieuropaei infection in humans was reported in 2017. Spirometra tapeworms exist worldwide and infection is common in animals, but S. erinaceieuropaei infections are rare in humans. Treatment for infection typically includes surgical removal and anti-worm medication.
The southern multimammate mouse or southern African mastomys is a species of rodent in the family Muridae which is endemic to southern Africa. It is called a multimammate mouse because it can have 8 to 12 pairs of mammae, in comparison other mouse species only have 5 pairs.
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The microfilaria is an early stage in the life cycle of certain parasitic nematodes in the family Onchocercidae. In these species, the adults live in a tissue or the circulatory system of vertebrates. They release microfilariae into the bloodstream of the vertebrate host. The microfilariae are taken up by blood-feeding arthropod vectors. In the intermediate host the microfilariae develop into infective larvae that can be transmitted to a new vertebrate host.
Capillaria hepatica is a parasitic nematode which causes hepatic capillariasis in rodents and numerous other mammal species, including humans. The life cycle of C. hepatica may be completed in a single host species. However, the eggs, which are laid in the liver, must mature outside of the host body prior to infecting a new host. So the death of the host in which the adults reach sexual maturity, either by being eaten or dying and decomposing, is necessary for completion of the life cycle.
Cestoda is a class of parasitic worms in the flatworm phylum (Platyhelminthes). Most of the species—and the best-known—are those in the subclass Eucestoda; they are ribbon-like worms as adults, known as tapeworms. Their bodies consist of many similar units known as proglottids—essentially packages of eggs which are regularly shed into the environment to infect other organisms. Species of the other subclass, Cestodaria, are mainly fish infecting parasites.
Baylisascaris procyonis, also known by the common name raccoon roundworm, is a roundworm nematode, found ubiquitously in raccoons, the definitive hosts. It is named after H. A. Baylis, who studied them in the 1920s–30s, and Greek askaris. Baylisascaris larvae in paratenic hosts can migrate, causing larva migrans. Baylisascariasis as the zoonotic infection of humans is rare, though extremely dangerous due to the ability of the parasite's larvae to migrate into brain tissue and cause damage. Concern for human infection has been increasing over the years due to urbanization of rural areas resulting in the increase in proximity and potential human interaction with raccoons.
Gnathostoma hispidum is a nematode (roundworm) that infects many vertebrate animals including humans. Infection of Gnathostoma hispidum, like many species of Gnathostoma causes the disease gnathostomiasis due to the migration of immature worms in the tissues.
Euschoengastia peromysci is a mite in the genus Euschoengastia of the family Trombiculidae. Recorded hosts include the cotton mouse and marsh rice rat in Georgia; the northern short-tailed shrew, northern red-backed vole, northern flying squirrel, rock vole, white-footed mouse, and deermouse in Tennessee; and northern red-backed vole, southern bog lemming, masked shrew, and eastern red squirrel in North Carolina, among others.
Behavior-altering parasites are parasites with two or more hosts, capable of causing changes in the behavior of one of their hosts to enhance their transmission, sometimes directly affecting the hosts' decision-making and behavior control mechanisms. They do this by making the intermediate host, where they may reproduce asexually, more likely to be eaten by a predator at a higher trophic level which becomes the definitive host where the parasite reproduces sexually; the mechanism is therefore sometimes called parasite increased trophic facilitation or parasite increased trophic transmission. Examples can be found in bacteria, protozoa, viruses, and animals. Parasites may also alter the host behaviour to increase protection of the parasites or their offspring; the term bodyguard manipulation is used for such mechanisms.
Hammondia hammondi is a species of obligate heteroxenous parasitic alveolates of domestic cats. Intracellular cysts develop mainly in striated muscle. After the ingestion of cysts by cats, a multiplicative cycle precedes the development of gametocytes in the epithelium of the small intestine. Oocyst shedding persists for 10 to 28 days followed by immunity. Cysts in skeletal muscle measure between 100 and 340 μm in length and 40 and 95 μm in width. Some of the intermediate hosts develop low levels of antibody and some cross-immunity against Toxoplasma.
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Cuterebra fontinella, the mouse bot fly, is a species of New World skin bot fly in the family Oestridae. C. fontinella is typically around 1 cm (0.39 in) in length with a black and yellow color pattern. C. fontinella develops by parasitizing nutrients from its host, typically the white-footed mouse. C. fontinella has even been known to parasitize humans in rare cases. Individuals parasitized by C. fontinella will develop a large bump on the skin that is indicative of parasitization.
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2) Tkach, V. V., & Swiderski, Z. P. (1995). Scanning electron microscopy of the rare nematode species Pterygodermatites bovieri (Nematoda: Rictatuliriidae), a parasite of bats. Folia parasitologica, 43(4), 301–304.
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4) Luong, L. T., & Hudson, P. J. (2012). Complex life cycle of Pterygodermatites peromysci, a trophically transmitted parasite of the white-footed mouse (Peromyscus leucopus). Parasitology research, 110(1), 483–487.
5) Krichbaum, K., Mahan, C. G., Steele, M. A., Turner, G., & Hudson, P. J. (2010). The potential role of Strongyloides robustus on parasite-mediated competition between two species of flying squirrels (Glaucomys). Journal of Wildlife Diseases, 46(1), 229–235.
6) Kinsella, J. M. (1991). Comparison of helminths of three species of mice, Podomys floridanus, Peromyscus gossypinus, and Peromyscus polionotus, from southern Florida. Canadian journal of zoology, 69(12), 3078–3083.
7) Luong, L. T., Grear, D. A., & Hudson, P. J. (2009). Male hosts are responsible for the transmission of a trophically transmitted parasite, Pterygodermatites peromysci, to the intermediate host in the absence of sex-biased infection.International journal for parasitology, 39(11), 1263–1268.