Ranking control options for tropical theileriosis in at-risk dairy cattle in Tunisia, using benefitcost analysis

Gharbi, Mohamed; Touay, A; Khayeche, M; Laarif, J; Jedidi, Mohamed; Sassi, Limam; Darghouth, Mohamed Aziz

doi:10.20506/rst.30.3.2074

Cited by 42 publications

(42 citation statements)

References 13 publications

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“…Vaccination with T. annulata ‐infected cell lines attenuated by in vitro propagation remains the only practical means of inducing immunity in cattle. This strategy has been adopted in several countries, whereby there is a tendency for using attenuated cell line vaccines derived from a local parasite isolate (Bilgic et al., ; Gharbi et al., ; Pipano & Shkap, ). The development of similar control strategies against T. parva has been constrained by the impractically high amounts of infected T‐cells required (Brown, ), since the transfer of schizonts from donor culture cells into cells of the recipient animal, a step required for successful induction of immunity, occurs at a lower frequency in T. parva compared with T. annulata (Dolan, ).…”

Section: Introductionmentioning

confidence: 99%

Serum‐free in vitro cultivation of Theileria annulata and Theileria parva schizont‐infected lymphocytes

Zweygarth

Nijhof

Knorr

et al. 2020

Transbound Emerg Dis

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Theileriosis is a tick‐borne disease caused by intracellular protozoa of the genus Theileria. The most important species in cattle are Theileria annulata and Theileria parva. Both species transform leucocyte host cells, resulting in their uncontrolled proliferation and immortalization. Vaccination with attenuated T. annulata‐infected cell lines is currently the only practical means of inducing immunity in cattle. Culture media for Theileria spp. typically contain 10%–20% foetal bovine serum (FBS). The use of FBS is associated with several disadvantages, such as batch‐to‐batch variation, safety and ethical concerns. In this study, the suitability of serum‐free media for the cultivation of Theileria‐transformed cell lines was examined. Three commercial serum‐free media (HL‐1, ISF‐1 and Hybridomed DIF 1000) were evaluated for their ability to support growth of the T. annulata A288 cell line. The generation doubling times were recorded for each medium and compared with those obtained with conventional FBS‐containing RPMI‐1640 medium. ISF‐1 gave the shortest generation doubling time, averaging 35.4 ± 2.8 hr, significantly shorter than the 52.2 ± 14.9 hr recorded for the conventional medium (p = .0011). ISF‐1 was subsequently tested with additional T. annulata strains. The doubling time of a Moroccan strain was significantly increased (65.4 ± 15.9 hr) compared with the control (47.7 ± 7.5 hr, p = .0004), whereas an Egyptian strain grew significantly faster in ISF‐1 medium (43.4 ± 6.5 hr vs. 89.3 ± 24.8 hr, p = .0001). The latter strain also showed an improved generation doubling time of 73.7 ± 21.9 hr in an animal origin‐free, serum‐free, protein‐free medium (PFHM II) compared with the control. Out of four South African T. parva strains and a Theileria strain isolated from roan antelope (Hippotragus equinus), only one T. parva strain could be propagated in ISF‐1 medium. The use of serum‐free medium may thus be suitable for some Theileria cell cultures and needs to be evaluated on a case‐by‐case basis. The relevance of Theileria cultivation in serum‐free media for applications such as vaccine development requires further examination.

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Section: Introductionmentioning

confidence: 99%

Serum‐free in vitro cultivation of Theileria annulata and Theileria parva schizont‐infected lymphocytes

Zweygarth

Nijhof

Knorr

et al. 2020

Transbound Emerg Dis

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“…Tropical theileriosis is one of the most important tick‐borne diseases affecting different cattle breeds (taurine and zebu cattle) as well as buffaloes (Darghouth, Preston, Kilani, & Bouattour, ). The disease is a serious impediment to livestock development in several African and Asian countries causing huge economic losses (Cicek, ; El Hussein, Majid, & Shawgi, ; Gharbi, ; Gharbi et al., ; Inci et al., ; Minjauw & Mcleod, ). The epidemiology of tropical theileriosis is complex as it involves mammalian host, pathogen and vector interactions.…”

Section: Introductionmentioning

confidence: 99%

Current status of tropical theileriosis in Northern Africa: A review of recent epidemiological investigations and implications for control

Gharbi

Darghouth

Elati

et al. 2020

Transbound Emerg Dis

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Tropical theileriosis caused by the apicomplexan hemoparasite Theileria annulata is a tick‐borne disease that constraints livestock production in parts of Europe, Asia and Africa. Four Hyalomma tick species transmit T. annulata in at least eight Africa countries (Mauritania, Morocco, Algeria, Tunisia, Egypt, Sudan, South Sudan and Ethiopia). The two dominant T. annulata vector ticks present in Africa, H. scupense and H. anatolicum, underlie two different patterns of transmission, which in turn greatly influence the epidemiology of tropical theileriosis. H. dromedarii and H. lusitanicum are also capable of transmitting T. annulata in North Africa, but their roles are associated with specific production systems and agro‐ecological contexts. The emergence of resistance to the most widely used theilericidal compound, buparvaquone, continues to limit the effectiveness of chemotherapy. In addition, acaricide use is increasingly becoming unsustainable. Deployable T. annulata attenuated live vaccines established from local strains in Tunisia, Sudan and Egypt are available, and recent work has indicated that these vaccines can be protective under conditions of natural transmission. However, vaccination programmes may vary over space and time due to differences in the prevalence of disease amongst cattle populations, as well seasonal variation in vector activity. We review recent descriptive and analytical surveys on the epidemiology of T. annulata infection with reference to (a) demographic aspects such as breeds and ages of cattle herds previously exposed to distinct T. annulata infection pressures and (b) seasonal dynamics of tick activity and disease transmission. We then discuss how the wider endemic patterns that we delineate can underpin the development and execution of future vaccination programmes. We also outline options for integrated control measures targeting tick vectors and husbandry practices.

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“…Both of the diseases cause high financial losses as a consequence of severe clinical illness in infected cattle but also of carrier state (Gharbi et al . , ). In Tunisia, tropical theileriosis is one of the most frequent summer diseases of cattle with annual declared clinical cases of more than 2500 (Bahri et al .…”

Section: Introductionmentioning

confidence: 99%

Molecular prevalence and phylogenetic analysis of Theileria annulata and Trypanosoma evansi in cattle in Northern Tunisia

Sallemi

Rjeibi

Rouatbi

et al. 2017

Veterinary Medicine & Sci

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The present study aimed to estimate the molecular prevalence of Theileria annulata and Trypanosoma evansi infection in cattle in Northern Tunisia. A total number of 96 cattle from five farms were evaluated. T. annulata and T. evansi prevalences were 61% [56/66] and 10% [7/13], respectively, at a confidence interval (CI) of 95%, while co‐infection was present in 6% [4/8] of the tested animals at a CI of 95%. There was a significant correlation between age and the prevalence of T. annulata infection, whereas, there was no significant association shown with the age of cattle and T. evansi infection. Sequence and phylogenetic analyses showed that the T. annulata Tams1 gene and T. evansi ITS1 rDNA gene were highly conserved with 97.1–100% and 98.3–100% sequence identity, respectively.

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Ranking control options for tropical theileriosis in at-risk dairy cattle in Tunisia, using benefitcost analysis

Cited by 42 publications

References 13 publications

Serum‐free in vitro cultivation of Theileria annulata and Theileria parva schizont‐infected lymphocytes

Serum‐free in vitro cultivation of Theileria annulata and Theileria parva schizont‐infected lymphocytes

Current status of tropical theileriosis in Northern Africa: A review of recent epidemiological investigations and implications for control

Molecular prevalence and phylogenetic analysis of Theileria annulata and Trypanosoma evansi in cattle in Northern Tunisia

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