Polychromophilus murinus
Polychromophilus murinus are obligate intracellular parasites that infect Vespertilionid bats. The parasite is transmitted via several species of Nyceribiidae. P. murinus plays a malarial-like role in a variety of Vespertillionid bat species, with a wide geological distribution. It follows a typical haemosporidian life cycle, with mature gametocytes of the parasite taking over the bat hosts red blood cells as the key sign of infection. P. murinus is recorded in Europe, Asia, and Madagascar, and one recording in Panama. There are no climatic or seasonal variables in relation to infection, but has sporadic periods of infection intensity in bat species. There is not a large or known pathogenic effect on the bat host; while it does burst red blood cells, there is a lower degree of infection compared to other malarial species, so it does not cause anemia. Fever is a possible sign of pathology, but since bats are heterotherms, it is argued whether fever is possible. Overall, there is no form of pathology agreed upon caused by P. murinus and no current treatment.
Phylogenetics / taxonomy
Polychromophilus parasites are a monophyletic clade with two genetically distinct subclades, P. melanipherus, and P. murinus. Chumnandee et al. quote previous works on other distinct subclades under Polychromophilus: P. adami, P. corradetti, and P. deanei. It should be noted however that these three species have limited and dated information. Another study on these three species by Rasoanoro et al. shows Polychromophilus sp. parasites in a range of bat hosts, while there were several unidentified genetically distinct species under the genus, a connection to P. adami, P. corradetti, or P. deanei was not noted.Polychromophilus's most recent common ancestor is the avian/reptilian Plasmodium, showing a distant relationship between Polychromophilus to Plasmodium and mammalian Hepatocystis.
Polychromophilus murinus is one genus under many of the family Plasmodiidae, which consists of five species: P. adami, - infects African Miniopterus bats. P. corradetti - infects African Miniopterus bats. P. deanei - infects Myotis nigricans. P. melanipherus - infects Miniopterus bats.P. murinus - infects Vespertilionidae bats.
Hosts / vectors
Bats
Polychromophilus murinus is reported to infect the family Vespertilionidae. The bat species below are recorded across different studies of where P. murinus was found, within different geological contexts.Species found with infection
Eptesicus serotinus, Kerivoula hardwickii, Laephotis capensis, Myotis bechsteinii, Myotis blythii, Myotis crypticus, Myotis daubentonii, Myotis goudoti, Myotis Myotis, Myotis nattereri, Myotis nigricans '', Myotis siligorensis, Neoromicia grandidieri, Nyctalus noctula, Scotophilus robustus, Vespertilio murinus''Bat flies
The family Nyceribiidae are wingless, permanent, obligate ectoparasitic bat flies. Bat flies are vectors for Polychromophilus parasites. Various species of Nyceribiidae are highly host-specific, although some infect multiple bat hosts, observations show a small amount of non-primary host infections. The bat flies listed below have been found to carry P. murinus to bat hosts, these species of bat fly can carry other Polychromophilus species as well.Species found with infection
Basilia nana, Basilia nattereri '', Nycteribia kolenatti , Nycteribia latreilii , Nycrteribia pediculuaria , Nycteribia vexata , Nycteribia schmidtlii, Penicillidia dufourii''Bat fly reproduction in relation to bats
Bat flies reproduce via viviparious puparity, the female bat flies lay the final larval stage onto the roost wall, and this 3rd instar larvae will develop into a puparium quickly, followed by three to four weeks of pupal development. The now-adult bat fly will exit the chrysalis when it senses a juvenile bat host nearby, introducing Polychromophilus murinus at early development.Life cycle
The Nycterbiidae species carry Polychromophilus murinus sporozoites through the salivary glands until they get a blood meal from the bat host. The sporozoites are then injected into the bat host while blood-feeding; in the host schizogony occurs in various organs of the reticuloendothelial system. This results in merozoites being released, that then invade erythrocytes, developing into sexual gametocytes when in the red blood cells, a key sign of infection by P. murinus ''. These gametocytes are taken back up by the bat fly, which then undergo sexual reproduction, producing an oocyst, which will then develop sporozoites on the gut wall of the vector. Effectively restarting the life cycle, these sporozoites will migrate to the salivary glands, then to a bat host during feeding.Vertical transmission of Polychromophilus murinus'' does not take place in either bat fly puparia or bat pups. Rather, it is exclusively directly transmitted from the bat flies blood feeding.
Cell structure
Gametocytes are large round to oval-shaped with a maximal diameter of 6-8 μm. Mature gametocytes within the bat host will take up majority of the red blood cell space, leaving only the edge of the red blood cell visible. Pigmentation granules are of similar shape to mouse droppings and are of irregular size and amount, typically occurring in clusters. Like many genuses under Plasmodiidae, there are hemozoin pigment grains which are scattered within the cytoplasm. On average between 14 - 25 dark pigments are in the cytoplasm. Female macrogametocytes have a round and well-bordered nucleus in a dense cytoplasm, while male microgametocytes are more oval-shaped with a lighter colored cytoplasm, and a diffuse, random, ill-defined nucleus; a distingushing characteristic of male microgametocytes of P. murinus.Distribution
Polychromophilus murinus has a sporadic infection rate, meaning there are unsteady increases and flat trends across different years and seasons. The most notable infection rates studied were during July - August of 2010, with a period of increase over the summer season, but this trend did not continue the next year. P. murinus infections have been recorded across Europe, Asia, Madagascar, and Panama.Geological prevalence
Polychromophilus murinus is geologically prevalent in Europe, Asia, Madagascar, and one recording in Panama. The parasite shows very little phylogeographical structure, due to its broad dispersal. Since there is a larger distribution in Europe of P. murinus, there are a far greater number of bats to have been infected in this geological range than compared to Asia, Madagascar, or Panama.European countries recorded with infection: Belgium, Bulgaria, France, Georgia, Germany, Hungary, Italy, Luxembourg, Netherlands, Romania, Russia, Slovenia, Spain, Switzerland, Turkey, the United Kingdom, Ukraine.
Bat species recorded in Europe with P. murinus:Myotis bechsteiniiMyotis blythiiMyotis capacciniiMyotis crypticusMyotis daubentoniiMyotis myotisMyotis nattereri
Bat fly species recorded in Europe with P. murinus: Basilia nanaBasilia nattereriNycteribia kolenatiiNycteribia pediculariaNycteribia schmidtliiNycteribia vexataPenicillidia dufourii
Asian countries recorded with infection ': Cambodia, Thailand
Bat species recorded in Asia with P. murinus:Kerivoula hardwickiiMyotis siligorensisScotophilus kuhlii
Bat fly species recorded in Asia with P. murinus:Nycteribia kolenatiiNycteribia pediculariaNycteribia schmidtliiNycteribia vexata
Madagascar and Panama'
In Madagascar, the recorded bat species that has been infected with P. murinus are Myotis goudoti and Scotophilus robustus, both infected by Nycteribiid flies. Within Panama, there one bat species recorded to have been infected; Myotis nigricans by a Nycteribiid fly.