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A Review on Crimean-Congo Hemorrhagic Fever Infections in Tunisia. Vector Borne Zoonotic Dis 2024. [PMID: 38457645 DOI: 10.1089/vbz.2023.0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2024] Open
Abstract
Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic tick-borne disease, caused by an arbovirus of the genus Orthonairovirus and the family Nairoviridae. Crimean-Congo hemorrhagic fever virus (CCHFV) is widespread in several regions of the world. While the virus is not pathogenic to all susceptible livestock and wild mammals, it can lead to severe hemorrhagic fever in humans. In this review, we compiled published data on CCHFV infections in humans, animals, and ticks in Tunisia. Based on that, we discussed the epidemiology and the distribution patterns of CCHFV infections highlighting the risk factors for this virus in the country. CCHF infection prevalence in humans was estimated to 2.76% (5/181) and 5% (2/38) in Tunisian febrile patients and Tunisian slaughterhouse workers, respectively. Concurrently, seroprevalence in domestic ungulates (sheep, goats, cattle, and dromedaries) ranged from zero to 89.7%, and only one Hyalomma impeltatum tick specimen collected from dromedaries in southern Tunisian was positive for CCHFV by reverse transcriptase-polymerase chain reaction (0.6%; 1/165). As Tunisian studies on CCHFV are geographically scattered and limited due to very small sample sizes, further studies are needed to improve the knowledge on the epidemiology of CCHF in Tunisia.
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Human-biting ticks and zoonotic tick-borne pathogens in North Africa: diversity, distribution, and trans-Mediterranean public health challenges. One Health 2023; 16:100547. [PMID: 37363219 PMCID: PMC10288109 DOI: 10.1016/j.onehlt.2023.100547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 06/28/2023] Open
Abstract
North Africa is home to more than 200 million people living across five developing economies (Egypt, Libya, Tunisia, Algeria, and Morocco) and two Spanish exclaves (Ceuta and Melilla), many of whom are impacted by ticks and tick-borne zoonoses. Populations in Europe are also increasingly vulnerable to North African ticks and tick-borne zoonoses due to a combination of climate change and the movement of ticks across the Mediterranean on migratory birds, human travellers, and trafficked wildlife. The human-biting ticks and tick-borne zoonoses in North Africa are reviewed along with their distribution in the region. We also assess present and future challenges associated with ticks and tick-borne zoonoses in North African and highlight opportunities for collaboration and coordination between governments in Europe and North Africa to address public health challenges posed by North African ticks and tick-borne zoonoses.
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Preliminary study on the seasonal questing of Ixodes ricinus group ticks in Ain Draham forest (north-western Tunisia) with analyses of their phylogenetic diversity. Vet Parasitol Reg Stud Reports 2022; 36:100786. [PMID: 36436908 DOI: 10.1016/j.vprsr.2022.100786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/24/2022] [Accepted: 09/20/2022] [Indexed: 01/13/2023]
Abstract
The present study aimed to investigate the activity dynamics of Ixodes ricinus group ticks in a forest located in north-western Tunisia (Aïn Draham, Jendouba District) and assess the variation of abiotic factors (temperature, Normalized Difference Vegetation Index and relative humidity) during one year survey from September 2016 to August 2017 using the dragging sampling method. A total of 116 questing ticks was collected from the vegetation consisting of 47 adults (19 females and 28 males, sex ratio M:F = 1.47), 45 nymphs and 24 larvae representing 40.5, 38.8 and 20.7% of the total collected specimens, respectively. Adult I. ricinus were collected during October-May, nymphs during May-August and larvae during July-September. There were statistically significant correlations between adult tick numbers and mean daily relative humidity (Pearson r = 0.77; p = 0.003) and mean daily temperature (r = -0.74; p = 0.006). The comparison of 16S rDNA sequences from 20 adult ticks of approximately 444 bp length showed variability among 11 sequences. There was a low genetic variability (<1%) among the I. ricinus isolates collected from the forest. The amplicons showed >99% identity with I. ricinus and Ixodes inopinatus sequences from different countries and published in GenBank. These results should be complemented by further surveys in other Tunisian regions to better understand the influence of environmental factors on the biology of I. ricinus and the occurrence of sympatric I. inopinatus ticks. Different molecular markers should be used for better understanding of their taxonomic status.
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Retrospective study of hemoparasites in cattle in southern Italy by reverse line blot hybridization. J Vet Med Sci 2014; 76:869-75. [PMID: 24614604 PMCID: PMC4108771 DOI: 10.1292/jvms.13-0365] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tick-borne diseases are widespread in tropical and temperate regions and are
responsible for important economic losses in those areas. In order to assess the presence
and prevalence of various pathogens in southern Italy, we retrospectively analyzed cattle
blood samples collected for a previous study in 2000 using reverse line blot (RLB)
hybridization. The study had been carried out in three regions of southern Italy on 1,500
randomly selected and apparently healthy adult cattle. RLB showed that 43.7% of the cattle
were positive for nine different species of hemoparasites with either a single infection
or a mixed infection. Theileria buffeli was the most common species
found, being present in 27.3% of the animals, followed by Anaplasma
marginale in 18.1%, Anaplasma centrale in 13.8%,
Babesia bigemina and Anaplasma bovis in 4.2%,
Anaplasma phagocytophilum in 1.7%, Babesia bovis in
1.6%, Babesia major in 0.2% and Babesia divergens in
0.1%. Complete blood counts showed different degrees of anemia in 363 animals (24.2%) and
of these, 169 were RLB-positive for at least one pathogen. Among the ticks that were
collected from the cattle, the following species were identified: Rhipicephalus
bursa, Ixodes ricinus, Hyalomma marginatum, Boophilus
annulatus, Dermacentor marginatus and
Haemaphysalis (sulcata, parva,
inermis and punctata). The results obtained confirmed
the spread of endemic tick-borne pathogens in the regions studied.
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New insights into the epidemiology of bovine piroplasmoses in Italy. Vet Parasitol 2011; 184:77-82. [PMID: 21864982 DOI: 10.1016/j.vetpar.2011.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Revised: 07/22/2011] [Accepted: 08/01/2011] [Indexed: 11/26/2022]
Abstract
Few studies have been published on bovine piroplasmoses in Italy, and therefore a clear picture of the epidemiology of these infections is difficult to obtain. Vertebrate and invertebrate hosts in Central and Northern Regions of Italy were investigated in 2005 and 2006, when microscopy, molecular tools and serological tests were applied to 468 blood samples drawn from cattle in order to evaluate the presence of these protozoa and identify possible risk factors. Ticks were also collected, identified and analyzed by molecular techniques. Microscopy identified 6.5% of the animals as positive, whereas PCR detected piroplasm DNA in 21.6%. BLAST analysis showed 67 amplicons (17.0%) referable to the Theileria sergenti/buffeli/orientalis group, 17 (4.3%) to Theileria annae, and 1 to Babesia divergens. Serology evidenced a prevalence of 45.4% for Babesia bovis, 17.4% for Babesia bigemina, and 34.9% for B. divergens. The 127 collected ticks were identified as belonging to 5 species, mostly represented by Rhipicephalus bursa, Hyalomma marginatum and Ixodes ricinus. Molecular analyses evidenced the presence of B. bovis and B. bigemina, in 3 and 5 ticks, respectively. Our findings suggest that different species of piroplasms are circulating in bovine populations in Central and Northern Italy, and provide new insights into the complex epidemiology of bovine piroplasmoses in Italy.
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Abstract
Descriptions of Babesia occultans have previously been restricted to sub-Saharan Africa. Here, we report the finding, for the first time, of this low or non-pathogenic bovine Babesia species in Tunisia, northern Africa. B. occultans DNA was detected by molecular methods in Hyalomma marginatum unfed ticks collected in 3 bioclimatic regions of Tunisia. The near-full-length 18S rRNA gene was sequenced and compared with related sequences retrieved from GenBank. Phylogenetic analysis indicated that other sequences deposited as Babesia sp. could also correspond to B. occultans, suggesting that this species may have a wide distribution in Mediterranean and Asiatic regions, and not only in sub-Saharan Africa as previously described. A B. occultans-specific Reverse Line Blot (RLB) oligonucleotide probe was designed for future epidemiological studies that would help to clarify this possibility.
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Abstract
A total 576 adult ixodid ticks, collected in seven sites in Northern Tunisia, were analysed for piroplasm infection. Reverse line blot analysis identified nine different piroplasms, with an overall prevalence of 22.7%. 17.8% were Theileria spp. positive, 8.5% were positive for Babesia spp. and 3.6% of ticks harboured both genera. Although, most of the positive ticks harboured a single infection (17%), mixed infections with two, three or four different piroplasm species were also detected (5.7%).
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A molecular survey of Theileria and Babesia parasites in cattle, with a note on the distribution of ticks in Tunisia. Parasitol Res 2008; 103:435-42. [PMID: 18458949 DOI: 10.1007/s00436-008-0995-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 04/07/2008] [Indexed: 10/22/2022]
Abstract
Between October and November 2006, a total of 278 bovine blood samples were examined, and 104 (37.4%) were positive for piroplasms by microscopy. A reverse line blot hybridisation with polymerase chain reaction detected Theileria annulata, T. buffeli, Babesia bovis and B. bigemina in cattle accounting for 48.6% of positive samples. The most frequently found species was T. buffeli, which was present in 39.2% of the samples. T. annulata was found in 48 samples (17.3%). Babesia infections were less frequently detected: B. bovis was found in 6.8% of the samples and B. bigemina in 4.3%. Mixed infections were detected in 45 samples, accounting for seven different combinations of species. Seven Ixodid tick species (Boophilus annulatus, Ixodes ricinus, Hyalomma marginatum, Hyalomma excavatum, Hyalomma detritum, Haemaphysalis punctata and Haemaphysalis sulcata) were collected from examined cattle in the 23 visited farms. I. ricinus was the dominant species (36%), mainly collected in the humid zone, while it seemed to be very rare in the semi-arid zone (where only 15 specimens were collected), whereas B. annulatus was the most commonly collected species in the sub-humid area (68.5% of ticks collected in this zone).
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Abstract
Most cases of human babesiosis are caused either by Babesia divergens in Europe or Babesia microti in America. B. microti, once regarded as a single species, occurs as a world-wide species complex and although both phenotypic and genotypic features lend support to suggestions that zoonotic B. microti may occur in Europe, convincing medical evidence is lacking. Several B. divergens-like parasites have emerged in the last few years, but 18S rRNA gene analysis suggests that B. divergens 'sensu stricto' is restricted to European (and North African) cattle. Some of the B. divergens-like parasites only differ from the bovine type by a few bases, and it remains to be determined whether this is sufficient to accord them separate species status. Comparative biology should support genetic data in taxonomic studies of both B. divergens and B. microti.
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Abstract
Babesia divergens is an intraerythrocytic protozoan parasite, transmitted by the tick Ixodes ricinus, and is the main agent of bovine babesiosis in Europe. It is not only a cause of significant loss to the cattle industry; it can also infect immunocompromised humans, causing medical emergencies characterized by rapid fulmination and parasitemias that may exceed 70%. The current emphasis in Europe on sustainable agriculture and extensification is likely to lead to an increase in vector tick populations with increased risk of infection. Despite the veterinary and zoonotic importance of this parasite, relatively little research has been carried out on B. divergens, and many questions regarding the parasite's epidemiology and the host's response remain unanswered. A better understanding of the species' biology and host-parasite interactions may lead to improved control mechanisms and new trends in vaccine and antibabesial drug development. This review provides the first comprehensive summary of B. divergens biology, including its morphology, life cycle, and host specificity, and the current state of knowledge of both human and bovine infections.
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Simultaneous detection of bovine Theileria and Babesia species by reverse line blot hybridization. J Clin Microbiol 1999; 37:1782-9. [PMID: 10325324 PMCID: PMC84950 DOI: 10.1128/jcm.37.6.1782-1789.1999] [Citation(s) in RCA: 397] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A reverse line blot (RLB) assay was developed for the identification of cattle carrying different species of Theileria and Babesia simultaneously. We included Theileria annulata, T. parva, T. mutans, T. taurotragi, and T. velifera in the assay, as well as parasites belonging to the T. sergenti-T. buffeli-T. orientalis group. The Babesia species included were Babesia bovis, B. bigemina, and B. divergens. The assay employs one set of primers for specific amplification of the rRNA gene V4 hypervariable regions of all Theileria and Babesia species. PCR products obtained from blood samples were hybridized to a membrane onto which nine species-specific oligonucleotides were covalently linked. Cross-reactions were not observed between any of the tested species. No DNA sequences from Bos taurus or other hemoparasites (Trypanosoma species, Cowdria ruminantium, Anaplasma marginale, and Ehrlichia species) were amplified. The sensitivity of the assay was determined at 0.000001% parasitemia, enabling detection of the carrier state of most parasites. Mixed DNAs from five different parasites were correctly identified. Moreover, blood samples from cattle experimentally infected with two different parasites reacted only with the corresponding species-specific oligonucleotides. Finally, RLB was used to screen blood samples collected from carrier cattle in two regions of Spain. T. annulata, T. orientalis, and B. bigemina were identified in these samples. In conclusion, the RLB is a versatile technique for simultaneous detection of all bovine tick-borne protozoan parasites. We recommend its use for integrated epidemiological monitoring of tick-borne disease, since RLB can also be used for screening ticks and can easily be expanded to include additional hemoparasite species.
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Infection of Ixodes ricinus (Acari: Ixodidae) by Borrelia burgdorferi sensu lato in North Africa. JOURNAL OF MEDICAL ENTOMOLOGY 1999; 36:216-218. [PMID: 10083761 DOI: 10.1093/jmedent/36.2.216] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Free-living adult Ixodes ricinus L, were collected in Amdoun, situated in the Kroumiry mountains in northwestern Tunisia (North Africa). Using direct fluorescence antibody assay, the infection rate of field-collected I. ricinus by Borrelia burgdorferi sensu lato was 30.5% (n = 72). No difference in infection rate was observed between male and female ticks. Spirochetes that had been isolated from I. ricinus from Ain Drahim (Kroumiry Mountains) in 1988 were identified as Borrelia lusitaniae (formerly genospecies PotiB2). This is the first identification of a genospecies of Borrelia burgdorferi sensu lato from the continent of Africa.
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