Morphological and molecular analysis of Ornithonyssus spp. (Acari: Macronyssidae) from small terrestrial mammals in Brazil

Abstract

Based on chaetotaxy of the dorsal shield, the taxonomic status of many species of Ornithonyssus has been considered invalid, resulting in the synonymy of all Brazilian Ornithonyssus from small terrestrial wild mammals into one of the following four species: Ornithonyssus bacoti (Hirst, 1913), Ornithonyssus matogrosso (Fonseca, 1954), Ornithonyssus pereirai (Fonseca, 1935) or Ornithonyssus wernecki (Fonseca, 1935). Despite the revision of this genus in 1980, including all known species worldwide, the knowledge of Ornithonyssus in Brazil has not progressed for more than 40 years. Considering the potential importance of these haematophagous mites in transmitting rickettsial disease agents to animals and humans, we have revised Ornithonyssus species collected from small mammals in Brazil by means of morphological and molecular studies. Types and other material deposited in the Acari Collection of the Instituto Butantan (IBSP) were examined in addition to recently collected specimens. Morphological and genetic analysis of the 16S rDNA mitochondrial gene revealed that small terrestrial mammals in Brazil are parasitized by six species of Ornithonyssus mites: Ornithonyssus brasiliensis (Fonseca, 1939), O. matogrosso, O. monteiroi (Fonseca, 1941), O. pereirai, O. vitzthumi (Fonseca, 1941), and O. wernecki. An illustrated key to females of the valid Brazilian species of Ornithonyssus is included, based on optical and scanning electron microscopy.

Laboratory Identification of Arthropod Ectoparasites

“…Identification to the genus or species level can be difficult and is best done by a trained specialist (i.e., acarologist or entomologist), as they are separated by microscopic examination of the mouthparts, respiratory tract, and various plates on the body. Good references are available for this purpose (65,(67)(68)(69). Distinguishing these zoonotic mites from Sarcoptes and Demodex can usually be performed in the clinical laboratory, and some laboratories choose to report them as "mite, not Sarcoptes scabiei or Demodex sp."…”

Avian mite dermatitis: an Italian case indicating the establishment and spread of Ornithonyssus bursa (Acari: Gamasida: Macronyssidae) (Berlese, 1888) in Europe

“…). In two specimens, recognizable as adult females, the shape of the shields and chelicerae and the arrangement of the setae could be compared with the keys indicated in the literature as characteristic of the four species consistent with our case: D. gallinae , O. sylviarum , O. bursa, and O. bacoti . Krantz and Walter's treatise was utilized for identification of categories from superorder to family level…”

“…Our specimens matched the keys for the identification of O. bursa (Table ), and the other three candidate species were excluded . Thus, mite infestation caused by O. bursa was diagnosed.…”

“…O. bacoti (elongated genital plate with an anterior, medial projection fitting into the posterior concavity of the sternal shield)…”

Effect of Forest Cover on Ectoparasites of Small Mammals in the Brazilian Atlantic Forest

“…Of the 20 species of ectoparasites identified, the highest amount of infestation was caused by Laelapidae mites (Nieri-Bastos et al 2004, Reis et al 2008). In the current study, Ixodidae ticks also infested both rodents and marsupials (Barros & Baggio 1992, Nieri-Bastos et al 2011. We encourage more studies assessing the specificity of these parasites in the choice of their host in the natural environment.…”