Prevalence and risk factors associated with tropical theileriosis in Egyptian dairy cattle

Abstract

Background and Aim: Theileria annulata is the most prevalent piroplasm infecting cattle across Egypt. Theileriosis is transmitted by ixodid ticks of the genus Hyalomma. This study aimed to estimate the prevalence of theileriosis in cattle and their associated risk factors for infection.

Materials and Methods: A total of 570 blood samples were collected from cattle from five governorates (administrative districts) in Egypt and examined using a polymerase chain reaction assay to estimate the prevalence of tropical theileriosis and assess the associated risk factors.

Results: The overall prevalence rate was 16.49%, with the Alexandria district having the highest prevalence. The results revealed that the risk of theileriosis was elevated in older cattle (odds ratio [OR]=8.9, 95% confidence interval [CI]: 3.6- 21.9), especially in summers (OR=3.07, 95% CI: 1.4-6.3). Cattle heavily infested with ticks were at particular risk (OR=3.05, 95% CI: 2.1-4.5), as were those to which acaricide had not been applied (OR=13.7, 95% CI: 5.6-33.6).

Conclusion: Understanding the risk factors associated with T. annulata infection and regular infection monitoring could reduce infection rates and economic losses and is essential for the implementation of efficient control programs.

Full text

Veterinary World, EISSN: 2231-0916 919
Veterinary World, EISSN: 2231-0916
Available at www.veterinaryworld.org/Vol.15/April-2022/14.pdf
RESEARCH ARTICLE
Open Access
Prevalence and risk factors associated with tropical theileriosis in
Egyptian dairy cattle
Abdelfattah Selim1, William Weir2 and Hanem Khater3
1. Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh 13736,
Egypt; 2. Institute of Biodiversity Animal Health and Comparative Medicine, School of Veterinary Medicine, College of
Medical, Veterinary and Life Sciences, University of Glasgow, 464 Bearsden Road, Glasgow, G61 1QH, UK; 3. Department
of Parasitology, Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt.
Corresponding author: Abdelfattah Selim, e-mail: abdelfattah.selim@fvtm.bu.edu.eg
Co-authors: WW: willie.weir@glasgow.ac.uk, HK: hanemkhater@gmail.com
Received: 24-01-2022, Accepted: 04-03-2022, Published online: 14-04-2022
doi: www.doi.org/10.14202/vetworld.2022.919-924 How to cite this article: Selim A, Weir W, Khater H (2022)
Prevalence and risk factors associated with tropical theileriosis in Egyptian dairy cattle, Veterinary World, 15(4): 919-924.
Abstract
Background and Aim: Theileria annulata is the most prevalent piroplasm infecting cattle across Egypt. Theileriosis is
transmitted by ixodid ticks of the genus Hyalomma. This study aimed to estimate the prevalence of theileriosis in cattle and
their associated risk factors for infection.
Materials and Methods: A total of 570 blood samples were collected from cattle from five governorates (administrative
districts) in Egypt and examined using a polymerase chain reaction assay to estimate the prevalence of tropical theileriosis
and assess the associated risk factors.
Results: The overall prevalence rate was 16.49%, with the Alexandria district having the highest prevalence. The results
revealed that the risk of theileriosis was elevated in older cattle (odds ratio [OR]=8.9, 95% confidence interval [CI]: 3.6-
21.9), especially in summers (OR=3.07, 95% CI: 1.4-6.3). Cattle heavily infested with ticks were at particular risk (OR=3.05,
95% CI: 2.1-4.5), as were those to which acaricide had not been applied (OR=13.7, 95% CI: 5.6-33.6).
Conclusion: Understanding the risk factors associated with T. annulata infection and regular infection monitoring could
reduce infection rates and economic losses and is essential for the implementation of efficient control programs.
Keywords: cattle, Egypt, polymerase chain reaction, risk factors, Theileria annulata.
Introduction
Ticks are obligate hematophagous ectoparasites
of humans and animals. They transmit more species
of pathogens than any other blood-feeding arthro-
pod [1-6] and require careful monitoring and con-
trol measures [7,8]. A variety of tick-borne diseases
affect animal productivity in developing countries [9].
Bovine tropical theileriosis is a tick-borne protozoal
disease caused by Theileria annulata and is transmit-
ted by ixodid ticks of the genus Hyalomma [10,11].
Theileriosis causes large financial losses to farmers
because of debility, direct death, morbidity, milk loss,
and control costs for acaricides, treatment, and vac-
cines [12]. Although T. annulata cause larger produc-
tivity losses in exotic cattle breeds and their crosses,
naive indigenous cattle, particularly calves and adults
under endemic instability, are also affected [13].
Furthermore, farmers’ coping strategies for acari-
cide failure, such as raising acaricide concentration
and application frequency or admixing acaricides,
accelerate resistance, deplete earnings, and exacerbate
poverty [14].
The disease occurs in many parts of the
world, including South Europe, Asia, and North
Africa [15,16]. The disease is characterized clinically
by enlarged lymph nodes during the lymphoprolifer-
ative phase, followed by pyrexia, anemia, and associ-
ated leukopenia during the lymphodestructive phase.
T. annulata has been reported in different loca-
tions in Egypt [17]. It can be detected using various
diagnostic methods [18,19]. A direct microscopic
smear is a rapid and cheap technique, but it provides
low sensitivity and is unsuitable for epidemiological
studies [20]. By contrast, polymerase chain reaction
(PCR)-based assays used to detect parasite DNA are
characterized by high sensitivity and may be used
to unequivocally identify the species of piroplasm
present [21]. Only a few studies have investigated
the epidemiology of tick-borne diseases in Egypt.
The previously reported prevalence of T. annulata
was 16.05% in the Menofia [22] and 11.31% in the
Gharbia [23] districts in North Egypt, and it was
11.1% in Qena [24] in South Egypt. Nevertheless,
these studies have focused on a restricted number of
locations [25,26].
Consequently, the study aimed to estimate the
molecular prevalence of T. annulata among cattle
across North Egypt and assess risk factors associated
with its infection across the region.
Copyright: Selim, et al. Open Access. This article is distributed under
the terms of the Creative Commons Attribution 4.0 International
License (http://creativecommons.org/licenses/by/4.0/), which
permits unrestricted use, distribution, and reproduction in any
medium, provided you give appropriate credit to the original
author(s) and the source, provide a link to the Creative Commons
license, and indicate if changes were made. The Creative Commons
Public Domain Dedication waiver (http://creativecommons.org/
publicdomain/zero/1.0/) applies to the data made available in this
article, unless otherwise stated.

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Materials and Methods
Ethical approval
The Internal Ethics Review Committee of the
Faculty of Veterinary Medicine, Benha University,
approved (Approval Number: BUFVTM) this study. All
sample collection activities followed ethical guidelines.
Study period and location
An epidemiological study was conducted from
April 2019 to March 2020 in five North Egyptian dis-
tricts, primarily Alexandria, Beheira, Kafr El Sheikh,
Qalyubia, and Menofia (Figure-1). These represent
agricultural regions with a high density of cattle
used for milk and beef production. All the selected
governorates (districts) are situated in the Nile Delta
region except Alexandria, which is located on the
Mediterranean Sea. The Delta region has a hot desert
climate (Köppen: BWh) like the rest of Egypt. The
hottest months in the Delta region are July and August,
with an average high temperature of 34°C. Winter
temperatures typically vary from 9°C at night to 19°C
during the day. The Nile Delta region gets quite humid
during the winter months because of colder tempera-
tures and some rain.
Sample size estimation
The sample size for the study was determined
using Cochran’s formula [27] as follows:
2
2
(1 )−
=
pp
nZ
e
Where, n is the sample size, Z is the level of confi-
dence required (95% confidence interval [CI]), p is the
expected prevalence (10.25) % for T. annulata, as previ-
ously reported in Egypt [17], and e is the required level
of precision 5% based on Pourhoseingholi et al. [28].
Sample collection
A total of 570 blood samples were collected from
dairy cattle representing the five selected governorates
(districts) in Egypt. The sample collection represents
both sexes (180 males and 390 females) during four
seasons (spring, summer, autumn, and winter), sev-
eral different breeds (93 Baladi, 210 Friesian, and 267
mixed), and three age groups (<2, 2-4, and >4 years).
In addition, managemental factors such as tick infesta-
tion and monthly application of acaricides were deter-
mined. Blood samples (5 mL) were collected from
the jugular vein using a vacuum tube with ethylene-
diaminetetraacetic acid and transported in an icebox
(4oC) to a Veterinary Diagnostic Laboratory, Benha
University, and preserved at −20°C for molecular
analysis.
Molecular analysis
Total genomic DNA was extracted from all
blood samples using a QIAamp® DNA Mini (Qiagen
GmbH, Hilden, Germany) kit following the manu-
facturer’s instructions. Extracted DNA was kept at
−20°C.
The PCR assay was performed using specific
primers targeting T. annulata Tams-1 gene, which
was evaluated by D’Oliveira et al. [29]. The for-
ward primer (5′-GTAACCTTTAAAAACGT-3′) and
reverse primer (5′-GTAACCTTTAAAAACGT-3′)
were used. The PCR reaction was performed in a
total volume of 25 µL, containing 12.5 µL Dream
Taq Green PCR master mix (2×) (Thermo Scientific,
Germany), 1 µL of each primer (20 pmol/µL), 5.5 µL
nuclease-free water, and 5 µL DNA template. The
PCR reaction was conducted at 94°C for 3 min fol-
lowed by 35 amplification cycles. Each cycle includes
a denaturation step at 95°C for 20 s, an annealing step
at 56°C for 45 s, and an extension step at 72°C for
50 s. There was also a final extension for 10 min at
72°C. The PCR products were separated and visual-
ized through electrophoresis (Cleaver Scientific Ltd,
UK) on a 1.5% agarose gel.
DNA sequencing
Two PCR products were randomly selected, puri-
fied, and cleaned for sequencing. Direct sequencing
was performed in both directions utilizing the same pair
of primers as the PCR reaction using the ABI PRISM®
BigDye™ Terminators v3.1 Cycle Sequencing Kit
(Applied Biosystems, USA). The obtained sequences
were trimmed using the BioEdit [30] program and
were compared with the NCBI non-redundant data-
base using the BLAST (https://blast.ncbi.nlm.nih.
gov) search tool. The sequences of two amplicons
were confirmed and represented T. annulata. They
were deposited in GenBank under accession numbers
LC549653 and LC549654.
Statistical analysis
The data were analyzed by statistical package
for the social sciences v 17.0 (IBM Corp., NY, USA)
using the Chi-square test. Differences were considered
significant if p<0.05. Logistic regression analysis was
performed to assess the effect of each variable on the
prevalence of T. annulata. The association between
Figure-1: Map showing the location of the study areas
[Map generated by QGIS software].

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T. annulata infection and factors was investigated using
univariable analysis. Risk factors, odds ratio (OR), and
CIs for each significant variable (p<0.2) were identi-
fied using a multivariable logistic regression model.
Results
Prevalence of T. annulata according to the locality
Overall, the prevalence rate of T. annulata
among cattle in the studied areas was 16.49%. The
Alexandria governorate had the highest prevalence
rate (22.58%) compared with Menofia, Beheira, Kafr
El Sheikh, and Qalyubia (14.62%, 13.91%, 12.22%,
and 16.25%, respectively) (Table-1). There was no
significant difference in the prevalence of T. annulata
among the different localities (p=0.1).
Univariate analysis of risk factors associated with
T. annulata infection
Univariate logistic regression analysis was per-
formed for six variables to assess the risk factors
that could affect T. annulata prevalence (Table-2).
The results showed that the prevalence of theilerio-
sis increased significantly (p=0.0001) with the age of
the examined animals, reaching 31.8% in older cat-
tle (>4 years old). In contrast, it was 3.5% in younger
animals (<2 years old) and 16.8% in the middle age
group (2-4 years old).
The prevalence of T. annulata showed a signif-
icant disparity between different seasons (p=0.0001),
with higher infection rates in autumn (24.1%) and
summer (21%) compared with winter (8.0%) and
spring (6.6%). Infection prevalence is strongly asso-
ciated with three other factors: The degree of tick
infestation, the frequency of acaricidal application,
and the animal’s age. Tick-infested cattle displayed a
higher prevalence of T. annulata than uninfected ani-
mals (28.4% vs. 9.2%, p=0.00001). Cattle not treated
with acaricides showed a far higher infection preva-
lence than those treated regularly (52.8% vs. 3.8%,
p=0.00001). The sex and breed of animals did not sig-
nificantly affect the prevalence of T. annulata infec-
tion (Table-2).
Multivariate logistic regression analysis
Based on the results of the univariate testing, four
risk factors were selected for multivariate analysis.
The significance and OR were calculated for animal
age, season sampled, level of tick infestation, and aca-
ricidal application frequency. Cattle over 4 years old
were found to be 8.9 times more likely to be positive
than those below 2 years old. Furthermore, the prev-
alence of T. annulata was 4 times higher in autumn
and 3 times higher in summer than that in spring. The
Table-1: Prevalence rate of Theileria annulata in cattle in examined areas.
Locality Number of examined animals Number of positive animals % 95% CI p-value
Alexandria 155 35 22.58 16.4-30.1 0.1**
Beheira 130 19 14.62 9.2-22.1
Kafr El Sheikh 115 16 13.91 8.4-21.9
Qalyubia 90 11 12.22 6.5-21.2
Menofia 80 13 16.25 9.2-26.5
Total 570 94 16.49 13.5-19.8
**The results are not significant at p<0.05. CI=Confidence interval
Table-2: Univariate analysis of associated risk factors for Theileria annulata infection.
Parameter Number of examined animals Number of positive % 95% CI p-value
Age
<2 140 5 3.5 1.3-8.5 0.0001*
2-4 320 54 16.8 13-21.5
>4 110 35 31.8 23.4-41.4
Sex
Male 180 25 13.9 9.3-20 0.2
Female 390 69 17.7 14.1-22
Breed
Baladi 93 15 16.1 9.6-25.5 0.5
Friesian 210 39 18.6 13.6-24.6
Mixed 267 40 15 11-20
Season
Spring 120 8 6.6 3.1-13.1 0.0001*
Summer 205 43 21 15.7-27.3
Autumn 145 35 24.1 17.6-32
Winter 100 8 8 3.7-15.6
Tick infestation
Yes 215 61 28.4 22.5-34.9 0.0001*
No 355 33 9.2 6.5-12.9
Acaricide application
Regular 130 5 3.8 1.4-9.2 0.0001*
Irregular 387 61 15.7 12.3-19.8
Not in use 53 28 52.8 38.7-66.4
95% CI=95% confidence interval. *The result is significant at p<0.05

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multivariate analysis indicated that infection prev-
alence was 3 times higher among cattle that exhib-
ited heavy tick infestation than uninfested animals.
Similarly, cattle exposed to acaricides are 14 times
less likely to be infested with ticks than those in which
acaricides were not used (Table-3).
Discussion
Tropical theileriosis is an endemic disease of cat-
tle in Egypt and is considered an impediment to live-
stock production due to the severe economic losses it
causes [26]. This study investigated the prevalence of
T. annulata infection in the Nile Delta and assessed
the risk factors associated with infection in this region.
Tropical theileriosis has been previously reported
in different localities of Egypt, with a prevalence rate
of 11.6% in North Egypt [17]. In the present study,
the overall prevalence across the five study areas was
16.5%. The highest rate was observed in Alexandria
(22.5%) and Menofia (16.2%). These data for
Menofia are in line with the previously reported rate
of 16.05% [22]. However, in every area, the preva-
lence was lower than the rate of 63.6% reported in the
El-Wady El-Gaded governorate in South Egypt [26].
The high prevalence could be attributed to the lower
cattle population, relatively higher temperatures
year-round, favoring tick prevalence, poor veterinary
observation or absence of veterinary care, and regular
application of acaricides. The Mediterranean climate
of the present study is characterized by rainfall in the
winter, moderate rain in autumn, and high temperature
in summer. Such seasonal fluctuations provide a suit-
able environment for tick propagation, which is the
sole vector of theileriosis [31-33].
The overall prevalence of T. annulata in this
study (18.33%) was lower than that reported in
Pakistan (29.9%) [9] and Sudan (39%) [34]. The vari-
ation in the prevalence of theileriosis between coun-
tries may be attributed to geographical or ecological
factors, animal breed, management practice, and tick
control [35-37].
The present study revealed that the prevalence
of theileriosis was higher in older (>4 years old) and
middle-aged (2-4 years old) cattle compared with
younger animals (<2 years old). These results agree
with the previous findings in Egypt, where younger
animals showed a lower prevalence of infection than
adults [34,38]. Because of the long-term nature of
infection with T. annulata, the higher prevalence in
older animals may reflect increased exposure to infec-
tion or management-associated factors. In contrast to
babesiosis, where inverse age immunity has been doc-
umented, this phenomenon has not been established
for tropical theileriosis.
Despite the non-significant difference in the
effect of sex and breed of examined animals on
the prevalence of theileriosis, the prevalence rate
was higher in female cattle, as shown in a previous
study [10,36]. Such findings could be related to stress
factors such as pregnancy, parturition, and milk pro-
duction [26]. This study revealed the low prevalence
rate among Friesian cattle compared with the other
breeds. This finding may be associated with a high
level of nutrition and regular application of acaricides,
which will reduce cattle exposure to tropical theileri-
osis [39,40].
This study indicated that no or irregular acaricide
application is constant with higher T. annulata infection
rates and vice versa. Similar findings were reported by
Miyama et al. [41] and Moumouni et al. [42]. Such
observation could be explained as ticks are the sole
vector of theileriosis and highlight the role of regular
acaricide application, which is one of the main strate-
gies for preventing the disease in a herd.
The present study’s seasonal finding indicated
that the highest prevalence rates occurred in autumn
and summer, which is in consistent with previous
findings [9,34]. The higher prevalence in the dry season
may be due to poor pasture conditions and inadequate
nutrition, resulting in a weakened immune system [43].
This evidence may be attributed to the higher number
of examined cattle in the summer season. Furthermore,
because ixodid ticks are the principal vectors of T. annu-
lata infection transmission, the high incidence of ixo-
did tick species during the summer season increases the
likelihood of infection with T. annulata.
Conclusion
An appreciable prevalence of T. annulata infec-
tion was recorded in all Nile Delta areas given that
tropical theileriosis is known to be endemic across
such regions. Risk factor analysis confirmed that the
tick infestation level is critical for the prevalence of
infection, especially among older cattle in autumn
and summer. Thus, regular monitoring of T. annulata
infection and tick control programs should be imple-
mented to decrease the infection rate and economic
losses.
Authors’ Contributions
AS, WW, and HK: Conceptualization, method-
ology, formal analysis, investigation, resources, data
Table-3: OR from logistic regression analysis of potential
risk factors associated with Theileria annulata infection.
Risk factor Comparative
parameter
OR 95% CI
Age <2 ref
2-4 4.7 1.9-11.5
>4 8.9 3.6-21.9
Season Spring ref
Summer 3.07 1.4-6.3
Autumn 3.6 1.7-7.5
Winter 1.2 0.46-3.08
Tick infestation No ref 2.1-4.5
Yes 3.05
Acaricide
application
Regular ref
Irregular 4.09 1.6-9.9
Not in use 13.7 5.6-33.6
95% CI=95% confidence interval, OR=Odds ratio

Veterinary World, EISSN: 2231-0916 923
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curation, and writing – original draft preparation. AS
and HK: Writing – review and editing. AS and HK:
Project administration. AS, WW, and HK: Funding
acquisition. All authors have read and approved the
final manuscript.
Acknowledgments
The study was funded by LEAP-Agri (A Long
term EU-Africa Research and Innovation Partnership
on Food and Innovation on Food and Nutrition
Security and Sustainable Agriculture), project No:
220-MeTVAC, as well as Science, Technology &
Innovation Funding Authority (STIFA), Egypt, Project
ID: 13520-220. Project title: “Ecosmart Alternative
Control Strategies against Theileria annulata and its
Tick Vectors”
Competing Interests
The authors declare that they have no competing
interests.
Publisher’s Note
Veterinary World remains neutral with regard
to jurisdictional claims in published map and institu-
tional affiliation.
References
1. Selim, A. and Khater, H. (2020) Seroprevalence and risk
factors associated with Equine piroplasmosis in North
Egypt. Comp. Immunol. Microbiol. Infect. Dis., 73: 101549.
2. Dantas-Torres, F., Chomel, B.B. and Otranto, D. (2012)
Ticks and tick-borne diseases: A one health perspective.
Trends Parasitol., 28(10): 437-446.
3. Selim, A., Almohammed, H., Abdelhady, A., Alouffi, A.
and Alshammari, F.A. (2021) Molecular detection and risk
factors for Anaplasma platys infection in dogs from Egypt.
Parasite.Vectors, 14(1): 429.
4. Selim, A., Alanazi, A.D., Sazmand, A. and Otranto, D.
(2021) Seroprevalence and associated risk factors for vec-
tor-borne pathogens in dogs from Egypt. Parasite. Vectors,
14: 175.
5. Said, M.B., Attia, K.A., Alsubki, R.A., Mohamed, A.A.,
Kimiko, I. and Selim, A. (2022) Molecular epidemiological
survey, genetic characterization and phylogenetic analysis
of Anaplasma ovis infecting sheep in Northern Egypt. Acta
Trop ., 229: 106370.
6. Alsubki, R.A., Albohairy, F.M., Attia, K.A., Kimiko, I.,
Selim, A. and Sayed-Ahmed, M.Z. (2022) Assessment of
seroprevalence and associated risk factors for anaplasmosis
in Camelus dromedarius. Vet. Sci., 9(2): 57.
7. Khater, H.F., Ramadan, M.Y. (2007) The acaricidal effect of
peracetic acid against Boophilus annulatus and Argas persi-
cus. Acta Sci. Vet., 35(1): 29-40.
8. Khater, H., Hendawy, N., Govindarajan, M., Murugan, K.
and Benelli, G. (2016) Photosensitizers in the fight against
ticks: Safranin as a novel photodynamic fluorescent aca-
ricide to control the camel tick Hyalomma dromedarii
(Ixodidae). Parasitol. Res., 115(10): 3747-3758.
9. Zeb, J., Shams, S., Din, I.U., Ayaz, S., Khan, A., Nasreen, N.,
Khan, H., Khan, M.A. and Senbill, H. (2020) Molecular
epidemiology and associated risk factors of Anaplasma
marginale and Theileria annulata in cattle from North-
Western Pakistan. Vet. Parasitol., 279: 109044.
10. Mohammed-Ahmed, G., Hassan, S., El Hussein, A. and
Salih, D. (2018) Molecular, serological and parasitologi-
cal survey of Theileria annulata in North Kordofan State,
Sudan. Vet. Parasitol. Reg. Stud. Rep., 13: 24-29.
11. Afifi, N., Shihata, I., El-Zorba, H. and Ismail, I. (2014)
Prevalence of theileriosis in cross-bred cattle: Its detection
through blood smear examination and polymerase chain
reaction in Dehradun district, Uttarakhand, India. Vet.
World, 7(3): 168.
12. Perera, P.K., Gasser, R.B., Firestone, S.M., Anderson, G.A.,
Malmo, J., Davis, G., Beggs, D.S. and Jabbar, A. (2014)
Oriental theileriosis in dairy cows causes a significant milk
production loss. Parasite. Vectors, 7: 1-8.
13. Kasaija, P.D., Estrada-Peña, A., Contreras, M., Kirunda, H.
and de la Fuente, J. (2021) Cattle ticks and tick-borne dis-
eases: A review of Uganda’s situation. Ticks Tick-borne
Dis., 12: 101756.
14. de la Fuente, J., Contreras, M., Kasaija, P.D., Gortazar, C.,
Ruiz-Fons, J.F., Mateo, R. and Kabi, F. (2019) Towards a
multidisciplinary approach to improve cattle health and pro-
duction in Uganda. Vaccines, 7(4): 165.
15. Pereira, A., Parreira, R., Cotão, A.J., Nunes, M.,
Vieira, M.L., Azevedo, F., Campino, L. and Maia, C. (2018)
Tick-borne bacteria and protozoa detected in ticks collected
from domestic animals and wildlife in central and Southern
Portugal. Ticks Tick-borne Dis., 9(2): 225-234.
16. Salih, D., Hussein, A.E., Kyule, M., Zessin, K.H., Ahmed, J.
and Seitzer, U. (2007) Determination of potential risk fac-
tors associated with Theileria annulata and Theileria parva
infections of cattle in the Sudan. Parasitol. Res., 101(5):
1285-1288.
17. Rizk, M.A., Salama, A., El-Sayed, S.A.E., Elsify, A.,
El-ashkar, M., Ibrahim, H., Youssef, M. and El-Khodery, S.
(2017) Animal level risk factors associated with Babesia
and Theileria infections in cattle in Egypt. Acta Parasitol.,
62: 796-804.
18. McFadden, A., Rawdon, T., Meyer, J., Makin, J., Morley, C.,
Clough, R., Tham, K., Müllner, P. and Geysen, D. (2011) An
outbreak of haemolytic anaemia associated with infection
of Theileria orientalis in naive cattle. N. Z. Vet. J., 59(2):
79-85.
19. Omer, O., El-Malik, K., Mahmoud, O., Haroun, E.,
Hawas, A., Sweeney, D. and Magzoub, M. (2002)
Haematological profiles in purebred cattle naturally infected
with Theileria annulata in Saudi Arabia. Vet. Parasitol.,
107(1-2): 161-168.
20. Calleja-Bueno, L., Sainz, Á., García-Sancho, M., Rodríguez-
Franco, F., González-Martín, J.V. and Villaescusa, A. (2017)
Molecular, epidemiological, haematological and biochemi-
cal evaluation in asymptomatic Theileria annulata infected
cattle from an endemic region in Spain. Ticks Tick-borne
Dis., 8(6): 936-941.
21. Zaeemi, M., Haddadzadeh, H., Khazraiinia, P., Kazemi, B.
and Bandehpour, M. (2011) Identification of different
Theileria species (Theileria lestoquardi, Theileria ovis, and
Theileria annulata) in naturally infected sheep using nested
PCR-RFLP. Parasitol. Res., 108(4): 837-843.
22. Nayel, M., El-Dakhly, K.M., Aboulaila, M., Elsify, A.,
Hassan, H., Ibrahim, E., Salama, A. and Yanai, T. (2012)
The use of different diagnostic tools for Babesia and
Theileria parasites in cattle in Menofia, Egypt. Parasitol.
Res., 111(3): 1019-1024.
23. Mohammed, E. and Elshahawy, I. (2017) The current prev-
alence of bovine babesiosis and theileriosis infection in
Egypt. Clin. Med. Images Int. J., 1(1): 00004.
24. Abdel-Rady, A., Kot, S., Mahmoud, R. and Ellah, A. (2008)
Clinical, diagnostic and therapeutic studies on theileriasis
(Theileria annulata) in cattle in upper Egypt. Suez Canal
Vet. Med. J., 13: 387-395.
25. El-Dakhly, K.M., Arafa, W.M., Soliman, S., Abdel-Fatah,
O.R., Wahba, A.A., Esteve-Gasent, M.D. and Holman, P.J.
(2020) Molecular detection, phylogenetic analysis, and
genetic diversity of Theileria annulata, Babesia bigem-
ina, and Anaplasma marginale in cattle in three districts of
Egypt. Acta Parasitol., 65(3): 620-627.

Veterinary World, EISSN: 2231-0916 924
Available at www.veterinaryworld.org/Vol.15/April-2022/14.pdf
26. Amira, A.H., Ahmed, L., Ahmed, J., Nijhof, A. and
Clausen, P.H. (2018) Epidemiological study on tropical thei-
leriosis (Theileria annulata infection) in the Egyptian Oases
with special reference to the molecular characterization of
Theileria spp. Ticks Tick-borne Dis., 9(6): 1489-1493.
27. Fleiss, J.L., Levin, B. and Paik, M.C. (2013) Statistical
Methods for Rates and Proportions. John Wiley and Sons,
New York.
28. Pourhoseingholi, M.A., Vahedi, M. and Rahimzadeh, M.
(2013) Sample size calculation in medical studies.
Gastroenterol. Hepatol. Bed Bench. 6(1): 14-17.
29. D’Oliveira, C., Van Der Weide, M., Habela, M.A.,
Jacquiet, P. and Jongejan, F. (1995) Detection of Theileria
annulata in blood samples of carrier cattle by PCR. J. Clin.
Microbiol., 33(10): 2665-2669.
30. Hall, T. (2004) BioEdit version 7.0. 0. Available from:
https://www.mbio.ncsu.edu/BioEdit/bioedit.html.
Retrieved on 31-03-2021.
31. Al-Saeed, A.T.M., Omer, L.T., Abdo, J., Habibi, G.,
Salih, D.A., Seitzer, U. and Ahmed, J. (2010)
Epidemiological studies on tropical theileriosis (Theileria
annulata infection of cattle) in Kurdistan Region, Iraq.
Parasitol. Res., 106(2): 403-407.
32. Selim, A., Marawan, M.A., Ali, A.F., Manaa, E. and
AbouelGhaut, H.A. (2020) Seroprevalence of bovine leuke-
mia virus in cattle, buffalo, and camel in Egypt. Trop. Anim.
Health Prod., 52(3): 1207-1210.
33. Selim, A., Radwan, A. and Arnaout, F. (2020) Seroprevalence
and molecular characterization of West Nile Virus in Egypt.
Comp. Immunol. Microbiol. Infect. Dis., 71: 101473.
34. Abaker, I.A., Salih, D.A., El Haj, L.M., Ahmed, R.E.,
Osman, M.M. and Ali, A.M. (2017) Prevalence of Theileria
annulata in dairy cattle in Nyala, South Darfur State, Sudan.
Vet. World, 10(12): 1475.
35. Cauvin, A., Hood, K., Shuman, R., Orange, J.,
Blackburn, J.K., Sayler, K.A. and Wisely, S.M. (2019) The
impact of vector control on the prevalence of Theileria cervi
in farmed Florida white-tailed deer, Odocoileus virginianus.
Parasit. Vectors, 12(1): 100.
36. Tayebwa, D.S., Vudriko, P., Tuvshintulga, B., Guswanto, A.,
Nugraha, A.B., Gantuya, S., Batiha, G.E.S., Musinguzi, S.P.,
Komugisha, M. and Bbira, J.S. (2018) Molecular epidemi-
ology of Babesia species, Theileria parva, and Anaplasma
marginale infecting cattle and the tick control malpractices
in Central and Eastern Uganda. Ticks Tick-borne Dis., 9(6):
1475-1483.
37. Selim, A., Megahed, A.A., Kandeel, S. and Abdelhady, A.
(2020) Risk factor analysis of bovine leukemia virus infec-
tion in dairy cattle in Egypt. Comp. Immunol. Microbiol.
Infect. Dis., 72: 101517.
38. Sallemi, S., Rjeibi, M.R., Rouatbi, M., Amairia, S., Ben
Said, M., Khbou, M.K. and Gharbi, M. (2018) Molecular
prevalence and phylogenetic analysis of Theileria annulata
and Trypanosoma evansi in cattle in Northern Tunisia. Vet.
Med. Sci., 4(1): 17-25.
39. Hailemariam, Z., Krücken, J., Baumann, M., Ahmed, J.S.,
Clausen, P.H. and Nijhof, A.M. (2017) Molecular detec-
tion of tick-borne pathogens in cattle from Southwestern
Ethiopia. PLoS One, 12(11): e0188248.
40. Muhanguzi, D., Matovu, E. and Waiswa, C. (2010)
Prevalence and characterization of Theileria and Babesia
species in cattle under different husbandry systems in
Western Uganda. Int. J. Anim. Vet. Adv., 2(2): 51-58.
41. Miyama, T., Byaruhanga, J., Okamura, I., Uchida, L.,
Muramatsu, Y., Mwebembezi, W., Vudriko, P. and
Makita, K. (2020) Effect of chemical tick control practices
on tick infestation and Theileria parva infection in an inten-
sive dairy production region of Uganda. Ticks Tick-borne
Dis., 11(4): 101438.
42. Moumouni, P.F.A., Aplogan, G.L., Katahira, H., Gao, Y.,
Guo, H., Efstratiou, A., Jirapattharasate, C., Wang, G.,
Liu, M. and Ringo, A.E. (2018) Prevalence, risk factors, and
genetic diversity of veterinary important tick-borne patho-
gens in cattle from Rhipicephalus microplus-invaded and
non-invaded areas of Benin. Ticks Tick-borne Dis., 9(3):
450-464.
43. Theodory, T.F. and Malipula, M. (2014) Climate change
and socio-economic vulnerability among Maasai pastoral
communities in Northern Tanzania. J. Policy Leadership,
2: 20-22.
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