For a better understanding of the complex coevolutionary processes between hosts and parasites, accurate identification of the actors involved in the interaction is of fundamental importance. Blood parasites of the Order Haemosporidia, responsible for malaria, have become the focus of a broad range of studies in evolutionary biology. Interestingly, molecular-based studies on avian malaria have revealed much higher species diversity than previously inferred with morphology. Meanwhile, studies on bat haemosporidian have been largely neglected. In Europe, only one genus (Polychromophilus) and two species have been morphologically described. To evaluate the presence of potential cryptic species and parasite prevalence, we undertook a molecular characterization of Polychromophilus in temperate zone bats. We used a nested-PCR approach on the cytochrome b mitochondrial gene to detect the presence of parasites in 237 bats belonging to four different species and in the dipteran bat fly Nycteribia kolenatii, previously described as being the vector of Polychromophilus. Polychromophilus murinus was found in the four bat species and in the insect vector with prevalence ranging from 4% for Myotis myotis to 51% for M. daubentoni. By sequencing 682 bp, we then investigated the phylogenetic relationships of Polychromophilus to other published malarial lineages. Seven haplotypes were found, all very closely related, suggesting the presence of a single species in our samples. These haplotypes formed a well-defined clade together with Haemosporidia of tropical bats, revealing a worldwide distribution of this parasite mostly neglected by malarial studies since the 1980s.

Disease in the dark: molecular characterization of Polychromophilus murinus in temperate zone bats revealed a worldwide distribution of this malaria-like disease.

Polychromophilus murinus, a malaria parasite of Chiroptera is reported from Myotis daubentoni in England. The vector was suspected to be the ectoparasitic Nycteribiid fly, Nycteribia kolenatii. N. kolenatii collected from wild-caught M. daubentoni were found to have oocysts on the midgut and sporozoites in the salivary glands. Wild-caught N. kolenatii were maintained on two wild-caught M. daubentoni harbouring heavy (patent) infections of P. murinus; both oocysts and sporozoites were found in these flies. The mature oocysts measured 52-71 micron in diameter. Sporozoites were straight or slightly crescentic and had a mean length of 7.4 micron. Electron microscopy of immature and mature oocysts revealed a morphology similar to that of malaria parasites. Sporozoites were also similar in structure to Plasmodium sporozoites and were found in the epithelial cells of the salivary gland and within the lumen; a cytostome was present and transverse sections revealed 21 microtubules arranged evenly around the periphery. Sporozoites were observed within the basement membrane of the salivary gland of N. kolenatii; such sporozoites appeared to be penetrating the gland, a process hitherto not described in malaria parasites. Rickettsia-like bodies were found within the cytoplasm of the epithelial cells of the salivary gland. Exflagellation of microgametocytes was achieved. An ultrastructural study of the gametocytes revealed a structure similar to that described in other Haemoproteidae. A common feature of infected erythrocytes was a projecting erythrocyte membrane. Attempts to find schizogony in impression smears and sections of tissues of two infected M. daubentoni were not successful.

Polychromophilus murinus: a malarial parasite of bats: life-history and ultrastructural studies.

The majority of Haemosporida species infect birds or reptiles, but many important genera, including Plasmodium, infect mammals. Dipteran vectors shared by avian, reptilian and mammalian Haemosporida, suggest multiple invasions of Mammalia during haemosporidian evolution; yet, phylogenetic analyses have detected only a single invasion event. Until now, several important mammal-infecting genera have been absent in these analyses. This study focuses on the evolutionary origin of Polychromophilus, a unique malaria genus that only infects bats (Microchiroptera) and is transmitted by bat flies (Nycteribiidae). Two species of Polychromophilus were obtained from wild bats caught in Switzerland. These were molecularly characterized using four genes (asl, clpc, coI, cytb) from the three different genomes (nucleus, apicoplast, mitochondrion). These data were then combined with data of 60 taxa of Haemosporida available in GenBank. Bayesian inference, maximum likelihood and a range of rooting methods were used to test specific hypotheses concerning the phylogenetic relationships between Polychromophilus and the other haemosporidian genera. The Polychromophilus melanipherus and Polychromophilus murinus samples show genetically distinct patterns and group according to species. The Bayesian tree topology suggests that the monophyletic clade of Polychromophilus falls within the avian/saurian clade of Plasmodium and directed hypothesis testing confirms the Plasmodium origin. Polychromophilus' ancestor was most likely a bird- or reptile-infecting Plasmodium before it switched to bats. The invasion of mammals as hosts has, therefore, not been a unique event in the evolutionary history of Haemosporida, despite the suspected costs of adapting to a new host. This was, moreover, accompanied by a switch in dipteran host.

https://serval.unil.ch/resource/serval:BIB_9A04FC37E593.P001/REF.pdf

The evolutionary host switches of Polychromophilus: a multi-gene phylogeny of the bat malaria genus suggests a second invasion of mammals by a haemosporidian parasite.

The chiropteran haemosporidian Polychromophilus melanipherus: A worldwide species complex restricted to the family Miniopteridae

Bats are the only mammals with the capacity of powered flight. Nearly 1,000 species can be found all over the world except in the northern and southern polar areas. They perform important ecosystem services such as control of insects, reseeding of cut forests and pollination of plants, which provide food for humans and animals. On the other side, they are also recognized to be natural reservoir hosts of a large variety of zoonotic diseases with the ability to cross species barriers. To date, more than 80 virus species of different groups and various parasites, which can cause several diseases have been isolated or detected in bats. Especially their high population density and gregarious roosting behaviour increase the likelihood of intra- and inter-species transmission of infections. Another important factor, which enables pathogens to spread long distances, is the migratory habit of some bat species, resulting in a great dispersal capacity. The transmission of pathogens from bats to humans or other animals occurs by direct contact with infected animals, their blood and tissue or through vector species. One of the most important vector groups are insects. With more than a million described species, they are the most diverse group of animals. Especially haematophagous groups such as Cimicidae, Culicidae or Phlebotominae are known as vectors for a variety of diseases. These include bacteria, protozoan and metazoan parasites as well as viruses. We focused on blood-feeding insects, because the presence of certain viruses in them as well as in bats comprises a potential virus transmission from bats to humans through mosquitoes or other blood-feeding insects. For this chapter, we could find 20 viruses from four different families and two parasitic pathogens detected in all three groups of haematophagous insects.

/pdf/bats-as-potential-reservoir-hosts-for-vector-borne-diseases-42xrn3hg1v.pdf

Bats as Potential Reservoir Hosts for Vector-Borne Diseases

Le genre Palychromophilus est constitue par deux ensembles d’especes tres differents que les auteurs ont groupes dans 2 sous-genres : a ) le sous-genre Polychromophilus , avec pour espece type P. (P. ) melanipherus Dionisi 1899, telle qu’elle a ete redefinie par Garnham (1973) : la morphologie des gametocytes est de type « malariae » ; b ) le sous- genre Bloccala, avec pour espece type P. (B. ) murinus Dionisi 1898 ; la morphologie des gametocytes est proche de celle des Hemoproteidae d’Oiseaux.Des Polychromophilus de Miniopteres d’Europe, d’Afrique et d’Australie ont ete etudies et decrits, en particulier 2 especes nouvelles africaines : P. (P. ) corradettii chez Miniopterus inflatus au Gabon et P. (P. ) adami chez Miniopterus m. minor au Congo- Brazzaville. Des formes de multiplication tissulaire nombreuses et variees ont ete trouvees, mais les infections etant generalement mixtes, il n’est pas possible de rattacher avec certitude les differents schizontes observes a un sous-genre determine. Cependant, les auteurs proposent une interpretation s’inspirant des affinites phyletiques des parasites. Ainsi sont classes : a ) dans le sous-genre Polychromophilus (gametocytes de type « malariae »), les schizontes tissulaires de grande taille, siegeant dans une cellule hote tres hypertrophiee entouree par une capsule et dont les noyaux sont, chez les stades âges, complexes et granuleux ; b ) au sous-genre Bioccala (gametocytes de type « oiseau »), les schizontes de petite taille (type Mer et Goldblum). De meme, la sporogonie observee chez les Nycteribies par divers auteurs serait celle du sous-genre Bioccala .

https://www.parasite-journal.org/articles/parasite/pdf/1980/01/parasite1980551p13.pdf

The genus Polychromophilus (Haemoproteidae, parasite of Microchiroptera).

L’examen sanguin et histologique des Epomops franqueti (Pteropinae) captures aux alentours de Makokou (Gabon) a montre que ces chauves-souris sont frequemment parasitees par un Hepatocyste que nous nommons Hepatocystis brosseti. Le foie est l’organe de predilection des schizontes, qui, a maturite, sont extracellulaires, polylobes, de taille moderee (250 µ) et pourvus d’une abondante colloide en flaques. Un seul schizonte a ete trouve dans la rate.

/pdf/hepatocystis-brosseti-n-sp-haemoproteidae-parasite-d-epomops-2onwon69f2.pdf

Hepatocystis brosseti n. sp., Haemoproteidae, parasite d'Epomops franqueti, Pteropinae, au Gabon.

The schizogony of Polychromophilus was partially known by the findings of Schingarew, Mer and Goldblum who demonstrated microschizonts in the reticulo-endothelial tissue. The present work completes these data by showing the presence of macroschizonts in the lungs of both African and European species. These schizonts are characterized by their large size, the hypertrophy of the host cell and its nucleus and the evolution of the parasite apparently slow when young, becoming rapid later.

G. Rosin

Papers

The genus Polychromophilus (Haemoproteidae, parasite of Microchiroptera).

Hepatocystis brosseti n. sp., Haemoproteidae, parasite d'Epomops franqueti, Pteropinae, au Gabon.

[The schizogony of Polychromophilus (Haemoproteidae), cosmopolitan parasite of Microchiroptera].