Effect of Meteorological Factors on Hyalomma Species Composition and Their Host Preference, Seasonal Prevalence and Infection Status to Crimean-Congo Haemorrhagic Fever in Iran

Abstract

Background: The impact of environmental factors and host on Hyalomma spp. community structure and abundance in the main Crimean-Congo haemorrhagic fever (CCHF) foci of Iran is largely unknown.

Methods: Biotic and abiotic factors, including host, temperature, humidity, altitude, Köppen-Geiger climate types, sea­son, and precipitation on Hyalomma spp. community structure and abundances in 11 provinces of Iran were investigat­ed. Additionally, the possible infection of ticks with CCHF virus was evaluated using reverse transcription PCR tech­nique.

Results: Species analyses demonstrated the presence of Hyalomma anatolicum, H. marginatum, H. dromedarii, H. asi­aticum, H. detritum and H. schulzei in the study area. Hyalomma anatolicum was the dominant species in the southern and northern parts, whereas H. dromedarii was distributed mostly in central parts of the country. The highest tick infestation was recognized in hot season. Spatial variation in tick relative density was observed between habitat types where more ticks were collected in deserts, semi-deserts, and Mediterranean habitats. Except for H. dromedarii, which was more preva­lent on camel (P= 0.044), there were no significant variations in the frequencies of other Hyalomma species on different hosts. Hyalomma anatolicum, H. dromedarii frequencies had significant positive and negative asso­ciation with tempera­ture and precipitation respectively. Also humidity has positive impact on H. asiaticum frequency.

Conclusion: Data presented here will help improve ecological models to forecast the distribution of Hyalomma spp. ticks, to evaluate the risk of CCHF and other tick-borne diseases, and to design proper vector control measures to sup­press Hyalomma populations in Iran.