Tick Fever Virus Research Articles

Crimean-Congo Hemorrhagic Fever Virus in Ticks from Migratory Birds, Morocco1

Crimean-Congo hemorrhagic fever virus was detected in ticks removed from migratory birds in Morocco. This finding demonstrates the circulation of this virus in northwestern Africa and supports the hypothesis that the virus can be introduced into Europe by infected ticks transported from Africa by migratory birds.

Molecular Detection of Crimean-Congo Hemorrhagic Fever Virus in Ticks in Qom Province, Iran, 2011-2012

Molecular Detection of Crimean-Congo Hemorrhagic Fever Virus in Ticks in Qom Province, Iran, 2011-2012

Crimean-Congo Hemorrhagic Fever Virus in Ticks from Imported Livestock, Egypt

To the Editor: Crimean Congo hemorrhagic fever, a tick-borne illness caused by Crimean Congo hemorrhagic fever virus (CCHFV), is endemic to Africa, the Balkans, the Middle East, and parts of Asia. The hard ticks (Ixodidae), especially those of the genus Hyalomma, serve as reservoirs and vectors for CCHFV, and a variety of animals, such as cattle, sheep, and camels, are considered amplifying hosts for the virus. Although CCHFV may cause little or no disease in zoonotic hosts, the virus can cause severe disease in humans who may be exposed by tick bites or by contact with blood or tissues from infected patients or animals (1). Surveillance for CCHFV in animal and vector populations provides an opportunity to monitor a disease of potentially severe impact. In North Africa and the Middle East, trade in live animals, meat, and meat products poses noticeable risk to human and animal health (2,3) and can serve as a mobile pool of diseases with potentially large economic and health effects. Animals often originate in distant areas of a country or its neighbors, where they may be exposed to zoonotic pathogens not endemic to their final location, and may collect vectors that carry additional pathogens. As part of a broader study examining occupational risk of exposure to vector-borne and zoonotic pathogens in a high-risk abattoir worker population, we collected ectoparasites from freshly-slaughtered livestock and examined them for CCHFV. This study and was conducted in compliance with the Animal Welfare Act and in accordance with the principles set forth in the Guide for the Care and Use of Laboratory Animals (4). Sample collection took place over a 2-week period in July 2009 at the Muneeb abattoir in the Giza Governorate of Egypt. Ectoparasites were removed from 43 freshly slaughtered animals by using blunt forceps and were placed in glass vials. In total, 342 ectoparasites were collected: 70 (20.5%) from 14 cattle, 52 (15.2%) from 17 buffalo, 6 (1.8%) from 2 sheep, and 214 (62.6%) from 10 camels. Cattle, buffalo, and sheep originated in Egypt; camels were imported from Sudan and Somalia. Ectoparasites were transported to US Naval Medical Research Unit No. 3 in Cairo, Egypt, for taxonomic identification and pathogen detection. Ninety-seven percent (334) of the ectoparasites were ticks from the family Ixodidae. The genus Hyalomma accounted for 254 (76.0%) of these ticks, including nearly all of those collected from sheep (100%) and camels (99.5%) but only 60.4% and 9.1% of those collected from buffalo and cattle, respectively. The remaining ticks of the family Ixodidae belonged to genus Boophilus. After identification, ticks were grouped into pools by species, sex, and animal source. RNA was then extracted by using the QIAamp Viral RNA Kit (QIAGEN, Valencia, CA, USA). CCHFV small fragment RNA was detected with SuperScript III Platinum SYBR Green One-Step qRT-PCR (Invitrogen, Carlsbad, CA, USA) and published primers as described (5). Of 138 pools tested (258 ticks of the genera Hyalomma and Boophilus), 6 pools were positive for CCHFV. These 6 pools contained ticks collected from 1 camel imported from Somalia and 4 from Sudan. One positive pool comprised female H. excavatum (Koch, 1844), and 5 comprised female H. dromedarii (Koch, 1844), both proven vectors of CCHFV. Sequence analysis showed that each CCHFV-positive pool contained an identical yet previously unrecorded 229-bp RNA fragment (GenBank accession no. {type:entrez-nucleotide,attrs:{text:JF706233,term_id:371444381}}JF706233; Figure). This fragment had 92% identity with many published CCHFV isolates (BLAST analysis [www.ncbi.nlm.nih.gov/BLAST], GenBank nonredundant database); however, most base changes were synonymous substitutions. Translated protein queries (tblastx) identified an amino acid (serine at codon 26) in this new variant that differed from all but 1 ({type:entrez-nucleotide,attrs:{text:AJ010648.1,term_id:10638944}}AJ010648.1) of the 100 most similar published sequences. The functional consequence of a S26N substitution is unknown but may be minimal because of the similar physicochemical properties of asparagine and serine. Figure Phylogenetic relationship of 110 Crimean-Congo hemorrhagic fever virus sequences obtained from this study (6 tick pools), the positive control, and 99 published isolates from GenBank. Sequences were aligned by using ClustalX (www.clustal.org), and a phylogenetic ... Despite the low number of camels sampled in this study, 5 of the 10 camels were found to harbor ticks carrying RNA from an undocumented variant of CCHF. Although none of the domestic animals harbored infected ticks, it is not possible to conclude if these data reflect importation of CCHFV or infection acquired within Egypt because details about conditions under which animals were kept before slaughter are unavailable. Previous serologic studies in Egypt have shown antibodies to CCHFV were prevalent among imported camels at a quarantine station in Aswan governorate (6) and among domestic cattle, buffalo, sheep, and goats in Sharkia Governorate (7). We plan to further investigate the presence of CCHFV within camel and ectoparasite populations in Egypt by expanding protocol activities to a camel market in the same area as the abattoir.

Crimean-Congo Hemorrhagic Fever Virus in Ticks, Southwestern Europe, 2010

Crimean-Congo Hemorrhagic Fever Virus in Ticks, Southwestern Europe, 2010

Crimean-Congo Hemorrhagic Fever Virus in Ticks Collected from Humans, Livestock, and Picnic Sites in the Hyperendemic Region of Turkey

During June and July 2007, about 3125 adult ticks were collected from humans, animals, and vegetation in a hyperendemic region (Sivas and Tokat) of Turkey. A total of 2193 ticks were pooled in 225 pools and screened for the Crimean Congo hemorrhagic fever virus (CCHFV) presence by antigen-capture enzyme-linked immunosorbent assay. Infection rates were calculated as the maximum likelihood estimation with 95% confidence intervals (CI). The dominant tick species was found to be Hyalomma marginatum with the following infestation rates in human, cattle and sheep, respectively: 47.43%, 66.07%, and 30.12%. Maximum likelihood estimation values of CCHFV in H. marginatum ticks collected from human, cattle, and sheep were 0.91% (CI 0.05-4.42), 2.10% (CI 1.12-3.64), and 3.11% (CI 1.18-6.87), respectively. CCHFV antigens were also demonstrated in Hyalomma excavatum, Haemaphysalis parva, and Boophilus annulatus ticks collected from cattle and Rhipicephalus bursa ticks from sheep. Our results suggest that the studied area might maintain its endemic properties in the near future unless effective tick control measures are implemented.

Experimental Colorado tick fever virus infection in Colorado mammals.

One hundred and twenty-four small mammals of six species were inoculated with three strains of Colorado tick fever (CTF) virus to define viremia and neutralizing (N) antibody responses. Adult Eutamias minimus and Eutamias embrinus, and juvenile Peromyscus maniculatus and Spermophilus lateralis, were highly susceptible to development of viremic infection. Adult S. lateralis and P. maniculatus were moderately susceptible (greater than or equal to 50% viremic). Five Sylvilagus nuttalli did not become viremic following experimental inoculation. Spermophilus richardsoni was also relatively resistant (less than or equal to 50% viremic). The longest duration of viremia (mean 15.8 days) and highest peak viremia levels (mean peak titer 10(3.9 plaque-forming units per ml) occurred in E. minimus. Adult E. umbrinus, juvenile S. lateralis, and juvenile P. maniculatus had moderate viremias. Adult S. lateralis and S. richardsoni often had short viremias during which virus was only intermittently detectable. N antibody production was most rapid in E. minimus in comparison with other species. In addition, N antibody persisted for 1 year in this species. In other species, many animals lost detectable antibody 5-11 months after infection. No significant differences were found in patterns of infection between three CTF virus strains. We conclude that of the six species inoculated, E. minimus is the best experimental host for CTF virus.

Colorado Tick Fever Pericarditis

To the Editor.— Colorado tick fever is an acute febrile illness of man caused by an arbovirus transmitted by ticks common to the mountain areas of the northwestern United States, recognized as a distinct entity since Becker's description in 1930.1Experimental studies have shown the laboratory illness to be little varied from the natural disease, including the classically described headache, myalgia, fever, prostration, and leukopenia.2Laboratory-acquired tick fever with complicating pericarditis has not been previously reported in man (C. M. Eklund, personal communication) despite a known association with myocarditis in laboratory animals.3 Report of a Case.— This 60-year-old virology laboratory research assistant with fever, fatigue, and backache of two days' duration had been working with a variety of arboviral agents preceding his illness. Ten days before the onset, he cut his finger while removing brain tissue from a mouse infected with tick fever virus. Marked fatigue and

African swine fever virus in ticks (Ornithodoros moubata, murray) collected from animal burrows in Tanzania.

AFRICAN swine fever (ASF) is an acute, contagious and highly lethal disease of domestic pigs; it is usually acquired in Africa by association with wild swine, especially warthogs, which are regarded as asymptomatic carriers of the causal virus (ASFV)1. Unfortunately the disease gained access to Portugal in 1957 and has since spread to Spain, Italy and, transitorily, to France. In European countries where it has established itself as an enzootic disease of domestic swine, it has caused and continues to cause great economic loss.

The Survival of Yellow Fever Virus in Ticks 1

The Survival of Yellow Fever Virus in Ticks 1