Detection of Borrelia persica Infection in Ornithodoros tholozani Using PCR Targeting rrs Gene and Xenodiagnosis.

BACKGROUND: Relapsing fever caused by Borrelia persica, is an acute tick-borne disease which is transmitted by soft ticks of Ornithodoros tholozani to human. METHODS: Value of PCR and xenodiagnosis for detection of B. persica in O. tholozani ticks was compared. Sixty-four Borrelia-free ticks were fed on infected guinea pigs and used for the experiments. For xenodiagnosis, a group of 32 ticks in subsequent blood meal were fed on sterile guinea pigs and the indication of B. persica in the animal blood was tested 5-14 days later by dark-field microscopy. For PCR, all 64 ticks were subjected to PCR against B. persica rrs gene (16S-rDNA). Also sensitivity of PCR in terms of minimum detectable number of spirochetes as well as the effects of tick sex and post digestion was tested. RESULTS: PCR revealed B. persica DNA in 98.4% ticks, in which B. persica were found in 25.0% by xenodiagnosis. PCR was enough sensitive to give positive results for DNA of 1 spirochete. PCR success rates were similar for male or female ticks. Course of time did not affect the efficacy of PCR and similar results were observed for ticks of immediately fed, semi- or completely gravid or completely digested blood ones. CONCLUSION: Our results indicate that due to very low specificity and time consuming, xenodiagnosis is not a useful method whereas PCR method has advantages for study the Borrelia prevalence in ticks.

Molecular epidemiology of Crimean- Congo hemorrhagic fever virus genome isolated from ticks of 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.

The epidemiology of tick-borne relapsing fever in Iran during 1997-2006.

BACKGROUND: Tick-borne relapsing fever is an acute febrile and endemic disease in Iran. For many reasons, the incidence of disease is on decrease, however tick-borne relapsing fever is still a health issue in the rural areas for travelers. This study was carried out during 1997-2006 to investigate the tick-borne relapsing fever in Iran. METHODS: Based on a cross-sectional, retrospective and descriptive study in all the provinces, the residents in the endemic areas who were febrile and suspicious to tick-borne relapsing fever were enrolled in the study. Tick-borne relapsing fever is a notifiable disease in Iran and the national communicable disease surveillance data were used through questionnaires. The infectivity of Ornithodoros species to Borrelia also was studied in two highly endemic areas including Hamadan and Qazvin provinces. RESULTS: During 1997-2006, a total of 1415 cases have been reported from the entire country. The highest prevalence was observed in year 2002 with the incidence rate of 0.41/100,000 population. Ardabil province is the first ranked infected area (625 out of 1415), followed by Hamadan, Zanjan, Kurdestan and Qazvin provinces sequentially. The disease is recorded during the whole year but its peak occurs during summer and autumn. There have been 87.6% of the cases recorded from June to November. Forty five percent of the infected cases were male and one third of the patients were under 5 years of age. Fifty four percent of the patients comprise the children under 10 years. Ninety two percent of the cases were living in rural areas where their dwellings were close to animal shelters. They were involved mainly with farming and animal husbandry activities. All the febrile patients with confirmed spirochetes in their blood samples were treated according to a national guideline for tick-borne relapsing fever treatment. Only 7% of the patients were hospitalized and 0.8% of them exhibited the Jarisch-Herxheimer reaction. The study of infectivity of Ornithodoros species to Borrelia revealed that Ornithodoros tholozani was infected with Borrelia persica and Ornithodoros erraticus with Borrelia microti. CONCLUSION: Travelers to the rural areas with high prevalence of the disease should be made aware of the risk of tick-borne relapsing fever and use of appropriate control measures. Communicable disease surveillance including tick-borne relapsing fever should be pursued as well.

Propetamphos resistance in Rhipicephalus bursa (Acari, Ixodidae).

Hard tick infestation is an important problem in both traditional and industrial animal husbandry as well as in veterinary and public health. Several acaricides have been used to control tick infestation in Iran. Poor control has been attributed to acaricide resistance in tick populations although this has not been demonstrated experimentally. In this study, susceptibility status to propetamphos (Blotic) of 2-3-week-old larvae of Rhipicephalus bursa, one of the most common tick species in Iran, was evaluated using the FAO recommended larval packet test (LPT) method with some modifications. Log dosage probit analysis of propetamphos dose-response regression lines produced a resistance ratio based on LC(50) in the most resistant strain of approximately 103-fold. Biochemical assays suggested that the tick strains contained multiple insecticide resistance mechanisms involving elevation of esterases, GSTs, MFOs and alteration of acetylcholinesterase. In light of this data, practical implications for pest and pesticide resistance management strategies are discussed.

Bionomics of Anopheles sacharovi in Ardebil province, northwestern Iran during a larval control program.

Studies were conducted on the ecology of Anopheles sacharovi over a period of 12 months in Parsabad and Germi counties, Ardebil province, Iran. The species was active from June to late November with one peak of activity in early August on the plain of Parsabad, and from late June to late November with one peak of activity in late August in mountainous areas of Germi. Chemical analysis of the water in larval habitats showed that the water contained calcium bicarbonate and sodium sulphate, and the limit of salinity was 263--414 mg/l. Dissection of A. sacharovi from three villages during July in Parsabad indicated a very low parity rates all were found negative for sporozoites. ELISA testing of 210 blood meals of the species, showed that few of those found in cowsheds or chicken coops had fed on humans, but of those found in bedrooms 38.5% had fed on humans. Insecticide susceptibility tests showed that the species is susceptible to malathion and propoxur but resistant to DDT and dieldrin.

[Toxoplasmosis in Iran. Results of a seroepidemiological study]. / Toxoplasmose en Iran. Résultats d'une étude séroépidémiologique.

A toxoplasmosis seroepidemiological survey was effected with 13,018 sera collected by stratified cluster random sampling method from 12 provinces in Iran. The samples were studied by indirect immunofluorescent assay (IFA) for the presence of Toxoplasma. In this study, 52.6% of the subjects were male and the remaining 47.4% were female. Anti-Toxoplasma antibody was detected in a total of 51.8% of the samples with no significant difference between male and female affected subjects. The distribution of the infected samples was also investigated in various age groups, the level of infection to Toxoplasma increasing from childhood, culminating to 30 years of age and gradually declining from there after. Between the various age groups, the 10-19 years old demonstrated a 50% increase in relative risk to the infection with high antibody titer. Within the provinces under study, the highest relative frequency of Toxoplasma antibody titer was indicated in Mazandaran province (20.5%), while the lowest frequency was detected in Hormozgan (2.9%). In general, there was a decrease in the number of infected samples from humid areas in north to dry provinces in south of Iran. In the clinical symptoms study, no significant difference between male and female patients was demonstrated. According to the type of clinical manifestation, lymphadenopathy and central nervous system symptoms (encephalitis) were respectively the most and the least frequent manifestations.