High infection of Anaplasma and Ehrlichia spp. among tick species collected from different geographical locations of Iran

Objective: To ascertain the prevalence of the Anaplasma/Ehrlichia infections in tick population within four provinces of Iran. Methods: A total of 384 tick specimens were collected from domestic animals inhabiting in four provinces (East Azerbaijan, Gilan, South Khorasan and Yazd). Specimens were identified based on morphological analysis. The detection of Anaplasma spp./Ehrlichia spp. within tick samples was carried out by nested PCR amplification of the 16S ribosomal RNA gene accompanied by DNA sequencing and analysis for verification. Results: A total of 10 tick species were identified as follows: Ornithodoros lahorensis (O. lahorensis) (44.8), Hyalomma dromedarii (15.6), Dermacentor marginatus (13.5), Hyalomma anatolicum (11.2), Hyalomma asiaticum (5.7), Hyalomma marginatum (4.9), Rhipicephalus sanguineus (2.3), Hyalomma detritum (1.0), Dermacentor niveus (0.5) and Argas persicus (0.3). The percentage distribution of Anaplasma/Ehrlichia was 55.5 (213) across 384 studied ticks. Conclusions: To the best of our knowledge, this is the first report of Anaplasma ovis infection in O. lahorensis in Iran. We also conjecture the prevalence of Ehrlichia spp. in Yazd Province based on sequencing results; also, it is suggested that O. lahorensis is a potential vector in the studied area. This survey highlights the importance of Argasidae family to verify and correlate their threat in causing anaplasmosis and other diseases in animals. © 2016 by the Asian Pacific Journal of Tropical Disease

Study on Ectoparasites of Rhombomys opimus, the Main Reservoir of Zoonotic Cutaneous leishmaniasis in Endemic Foci in Iran

 Background: Ectoparasites of mammalian hosts play an important role for transmission of diseases from the host res­ervoirs to human. The aim of this study was to determine the species composition and infestation parameters for para­sitic arthropods associated with Rhombomys opimus. Methods: Ectoparasites of R. opimus were collected from seven endemic district of ZCL in Iran including Shirvan and Sfaraysen in North Khorasan Province, Kalaleh in Golestan Province, Damghan and Shahrood in Semnan Prov­ince, and Badrood and Habibabad in Isfahan Province. The areas of study were mainly desert and plain. Rodents were captured using Sherman life traps during active seasons from May to November 2008. Captured rodents were trans­ported to laboratory and their ectoparasites were picked up using brushing against the fur of the rodents. Ecto­parasites were stored in 70% ethanol for their preservation and then identified based on morphological characters. Results: Ectoparasites belonged to one flea species of Xenopsylla nuttalli and one mite species of Ornithonussus ba­coti. The flea species with 75.3% was more common than the mite. O. bacoti might play an important role in trans­mission of rat mite dermatitis among R. opimus colony. Conclusion: Results will provide an essential clue for combating zoonotic diseases in the region

Atomic view into Plasmodium actin polymerization, ATP hydrolysis, and fragmentation

Abstract Plasmodium actins form very short filaments and have a noncanonical link between ATP hydrolysis and polymerization. Long filaments are detrimental to the parasites, but the structural factors constraining Plasmodium microfilament lengths have remained unknown. Using high-resolution crystallography, we show that magnesium binding causes a slight flattening of the Plasmodium actin I monomer, and subsequent phosphate release results in a more twisted conformation. Thus, the Mg-bound monomer is closer in conformation to filamentous (F) actin than the Ca form, and this likely facilitates polymerization. A coordinated potassium ion resides in the active site during hydrolysis and leaves together with the phosphate, a process governed by the position of the Arg178/Asp180-containing A loop. Asp180 interacts with either Lys270 or His74, depending on the protonation state of the histidine, while Arg178 links the inner and outer domains (ID and OD) of the actin protomer. Hence, the A loop acts as a switch between stable and unstable filament conformations, the latter leading to fragmentation. Our data provide a comprehensive model for polymerization, ATP hydrolysis and phosphate release, and fragmentation of parasite microfilaments. Similar mechanisms may well exist in canonical actins, although fragmentation is much less favorable due to several subtle sequence differences as well as the methylation of His73, which is absent on the corresponding His74 in Plasmodium actin I