Biocontrol of pigeon tick Argas reflexus (Acari: Argasidae) by entomopathogenic fungus Metarhizium Anisopliae (Ascomycota: Hypocreales)

The pigeon tick Argas reflexus is a pathogen-transmitting soft tick that typically feeds on pigeons, but can also attack humans causing local and systemic reactions. Chemical control is made difficult due to environmental contamination and resistance development. As a result, there is much interest in increasing the role of other strategies like biological control. In this study, the efficacy of three strains (V245, 685 and 715C) of entomopathogenic fungus Metarhizium anisopliae for biological control of three life stages of pigeon tick A. reflexus including eggs, larvae, engorged and unfed adults was investigated under laboratory conditions. Five concentrations of different strains of M. anisopliae ranging from 10³ to 10(7) conidia/ml were used. All fungal strains significantly decreased hatchability of A. reflexus eggs. Strain V245 was the most effective strain on the mortality of larval stage with nearly 100 percent mortality at the lowest concentration (10³ conidia/ml) at 10 days post-inoculation. The mortality rate of both engorged and unfed adult ticks were also increased significantly exposed to different conidial concentrations compared to the control groups (P < 0.05) making this fungus a potential biological control agent of pigeon tick reducing the use of chemical acaricides.

Molecular epidemiology of crimean-congo hemorrhagic fever virus genome isolated of ticks from Hamadan province of Iran.

Background & objectives: Crimean-Congo hemorrhagic fever (CCHF) virus is a tick-borne member of the genus Nairovirus, family Bunyaviridae. CCHFV has been isolated from at least 31 different tick species. The virus is transmitted through the bite of an infected tick, or by direct contact with CCHFV-infected patients or the products of infected livestock. This study was undertaken to study the genetic relationship and distribution of CCHFV in the tick population of Hamadan province of Iran. Method: In this study, RT-PCR has been used for detection of the CCHFV genome. Results: This genome was detected in 19.2% of the ticks collected from livestock of different regions of the Hamadan province in western Iran. The infected species belonged to Hyalomma detritum, H. anatolicum, Rhipicephalus sanguineus and Argas reflexus. With one exception, genetic analysis of the virus genome isolates showed high sequence identity to each other. Even though they clustered in the same group with the strain circulating in Iran, they had a closer relationship to the Matin strain. Interpretation & conclusion: Vector control programs should be applied for reducing population density of potential tick vectors in this province. Further surveys are indicated in this region to provide a better view of the distribution and epidemiology of the virus.