INCIDENCE OF ANAPLASMOSIS AND FMD IN CAMEL (Camelus dromedaries)

Document Type : Research article

Authors

1 Veterinary Serum and Vaccine Research Institute, Abbasia, Cairo, Egypt

2 National Agriculture and Animal Resources Research Center, Ministry of Agriculture, Riyadh. KSA

3 National Agriculture and Animal Resources Research Center, Ministry of Agriculture, Riyadh

Abstract

A total of138 whole blood and serum samples were collected from camels (Camelus dromedaries) aged 3~10 years, with suspected clinical symptoms of blood parasites from May to August 2011, at different middle regions of Al-Riyadh Province in the Kingdom of Saudi Arabia (Al-Riyadh, Thumamah, Dawadmi and Wadi Al-Dawasir). Clinically the suspected infected camels with anaplasmosis showed signs of pale mucous membranes, rough hair coat, lacrimation, and ticks were noticed and detected on several locations at the camel's body. A total of 32 samples (23.19%) were microscopically positive for Anaplasma marginale (with parasitaemia 3-5%). All samples were tested by an indirect Enzyme Linked Immunosobent Assay (3-ABC-ELISA) which is specific to detect antibodies of foot and mouth disease virus (FMDV) infection. ELISA results revealed that 19 (13.76%) serum samples were positive; all these samples were positive for Anaplasma marginale. Meanwhile, the animals not showed any clinical FMD symptoms. This study revealed moderate infection of Anaplasma marginale, as well as concurrent incidence of FMD among camels in KSA. It would be of great interest to know if dromedaries play a role in transmitting the FMDV.

Keywords


INCIDENCE OF ANAPLASMOSIS AND FMD IN CAMEL (Camelus dromedaries)

 

R.M. Al-Khatib1,2, K.S. Mazloum 3, and H.M. Al Nakhli 3

 

1Veterinary Serum and Vaccine Research Institute, Abbasia, Cairo, Egypt

2Central Veterinary Diagnostic Lab, Ministry of Agriculture, Riyadh. KSA.

3National Agriculture and AnimalResourcesResearchCenter, Ministry of Agriculture, Riyadh. KSA

 

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                                      ABSTRACT

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Received at: 26/2/2012     

 

 

Accepted: 8/3/2012

A total of138 whole blood and serum samples were collected from camels (Camelus dromedaries) aged 3~10 years, with suspected clinical symptoms of blood parasites from May to August 2011, at different middle regions of Al-Riyadh Province in the Kingdom of Saudi Arabia (Al-Riyadh, Thumamah, Dawadmi and Wadi Al-Dawasir). Clinically the suspected infected camels with anaplasmosis showed signs of pale mucous membranes, rough hair coat, lacrimation, and ticks were noticed and detected on several locations at the camel's body. A total of 32 samples (23.19%) were microscopically positive for Anaplasma marginale (with parasitaemia 3-5%). All samples were tested by an indirect Enzyme Linked Immunosobent Assay (3-ABC-ELISA) which is specific to detect antibodies of foot and mouth disease virus (FMDV) infection. ELISA results revealed that 19 (13.76%) serum samples were positive; all these samples were positive for Anaplasma marginale. Meanwhile, the animals not showed any clinical FMD symptoms. This study revealed moderate infection of Anaplasma marginale, as well as concurrent incidence of FMD among camels in KSA. It would be of great interest to know if dromedaries play a role in transmitting the FMDV.

 

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Key words: Anaplasma marginale, Camel, FMD, immunosuppression, 3-AB, ELISA.

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إنتشار مرض الحمى القلاعية والانابلازما مرجينال في الجمال (وحيدة السنام)

 

رجب محمد الخطيب , کمال صابر مظلوم , حبيب مقبول النخلى

 

تم جمع 138 عينة من الدم الکامل والمصل من الجمال التي يتراوح أعمارها من 3-10 سنوات والتي يظهر عليها إعراض سريريه لمرض الانابلازما وذلک من شهر مايو إلى شهر اغسطس2011 من المناطق الوسطى بمحافظة الرياض بالمملکة العربية السعودية (الرياض والثمامة والدوادمى ووادي الدواسر). الجمال محل الدراسة کانت عليها علامات شحوب الأغشية المخاطية وخشونة في الشعر ودمعان مع تواجد القراد على أماکن متفرقة من الجسم.   أظهرت نتائج فحص الشرائح الدموية ان عدد 32 عينة کانت ايجابية لوجود طفيل الانابلازما مرجينال بنسبة (23.19%). وباستخدام تفاعل الإنزيم المناعي المرتبط الغير المباشرة (3ABC-ELISA) والدال علي سبق الإصابة بفيروس مرض الحمي القلاعية وجد أن 19 عينة مصل کانت ايجابية لوجود الأجسام المضادة لمرض الحمى القلاعية بنسبة (13.76%) کما أن هذه العينات کانت إيجابية للإصابة بطفيل الانابلازما مرجينال وفى نفس الوقت لم تظهر اى أعراض لمرض الحمى القلاعية على هذه الحيوانات. کشفت الدراسة عن أن الإصابة بالانابلازما مارجينال معتدلة, فضلا عن انتشار مرض الحمى القلاعية بين الإبل في المملکة العربية السعودية، هذا وسيکون من الأهمية معرفة إذا کانت الجمال تلعب دوراً في نقل مرض الحمى القلاعية، وبالإضافة إلى ذلک يلزم إجراء دراسات لتقييم دور قمع المناعة لانابلازما مارجينالي للإصابة بمرض الحمى القلاعية في الجمال، على أية حال؛ من المستحسن تطبيق برنامج التطعيم لقطعان الجمال ضد مرض الحمى القلاعية لتجنب انتشار المرض بين الجمال وخاصة الحاملة للفيروس والذي يعيش معظمهم في اتصال بحيوانات المزرعة الأخرى القابلة للعدوى.

 

Introduction

 

In the Saudi Arabia, It is well known that camels are resistant to many infectious diseases, due to their physiological attributes, camels are the most suitable species of domestic mammals to be used under extremely arid conditions (Seri et al., 2003; Bikaner, 2008). Despite the general reputation for hardiness and resilience, camels are, however, vulnerable to many infections (Wernery et al., 2004) and parasitic agents (Bukachi et al., 2003; Mohammed et al., 2007).

Anaplasmais one of the most important parasites transmitted by at least 20 tick species (Marchette and Stiller, 1982), but mostly Boophilus microplus causing anaplasmosis(TFRC, 1996).Anaplasmaparasite is responsible for a severe hemolytic disease, anaplasmosis; is usually caused by Anaplasma marginale (Kocan et al., 2000). Anaplasmosis is an infectious, non contagious, tick born disease of domesticated and wild ruminants. Fever, progressive anemia, digestive disturbances, emaciation are the main characteristics of this disease (Kocan et al., 2003). The disease has a worldwide distribution, particularly in tropical and sub-tropical regions. It has been also recorded in some temperate areas, the disease occur sporadically or as outbreaks leading to substantial significant economic losses (Smith, 1996).

Immunosuppressive effects are seem to be most of the time observed for various pathogenic agents, in particular in tick-borne diseases, as babesioses with other parasites in mice, or anaplasmosis (Persing, 1997). Studies of anaplasmosis in camels in KSA are sparse and little information had been provided.

Foot-and-mouth disease (FMD) is highly contagious viral disease that affectsall species of cloven-hoofed animals and wildlife

 

exposure to infection. It is possible that breeding, age, nutrition and concurrent disease may play a role in influencing the magnitude of the antibody response to FMDV, in addition; certain concurrent disease present in the animal at the time of infection can reduce immune response (Muneer et al., 1988).

During the course of parasitic infections, the host’s immunologic response to FMD virus is often depressed (Sharpe et al., 1982, Sharpe and Langley, 1983, Ahmad et al., 1991, Scott et al., 1977).

Although many of the clinical and pathologic features of the Anaplasma marginale, as well FMD are well recognized in animals, the role of immunosuppression of Anaplasma marginale in the outcome of FMD infection in camel is poorly studied.

The objective of this study was to investigate the incidence of Anaplasma marginale and FMD among camels in Saudi Arabia in viewing the effect of immunosuppression due to infection of camel with Anaplasma marginale on susceptibility of camel to FMDV infection.

 

MATERIALS and METHODS

 

Animals and area of study: The study were conducted on 138 Arabian (male and female) one-humped camels (Camelus dromedaries), 3~10 years old. The study was carried out in different middle regions of Al-RiyadhProvince in the Kingdom of Saudi Arabia (Al-Riyadh,Thumamah, Dawadmi and Wadi Al-Dawasir).

Blood samples: Ten milliliter of blood were drained from each animal by Jugular Vein-puncture, then 5 ml of blood mixed with EDTA used for blood film and stained with Giemsa. The remaining (5ml) clotted blood was centrifuged at 3000 rpm. The serum was aspirated and stored at 20oC until used.

 

 

 

 

 

including cattle, buffalo, sheep, goat, pig, elephant, camel and deer, leading to severe economic loss of livestock industries worldwide (Somsak, 2004, Valarcher et al., 2004). The Office International des Epizooties (OIE) code chapter on FMD includes camelids as being susceptible species to FMD, giving the impression that they are similar to cattle, sheep, goats and pigs in their potential involvement in the epidemiology of FMD (Wernery and Kaaden, 2004).

Amongst the camelidae, Bactrian camels and new world camelids have been shown to be susceptible to FMD virus (Larska et al., 2008). FMDV is present in camels even without clinical signs and camel can be a source of infection for cattle and other animals. Two serotypes (O and A) of FMDV were detected in both species (camel and cattle) by RT-PCR in Egypt (El Hakim, 2005). The presence of antibodies to FMDV in camel sera was reported in Sharkia province Egypt, (Moussa et al., 1970). Shiilegdamba et al. (2008) were reported 44 FMD outbreaks that affected cattle, sheep, goats, and camels in Mongolia.

During the 1981 outbreak of FMD at the Assam Zoo (India), a large number of wild ungulates including members of the family Camelidae, became infected (Sarma et al., 1983). It has been reported that dromedaries can contract the disease following experimental infection and via close contact with FMD diseased livestock (Kitching, 2002). Virus isolation and ELISA are the gold standard tests for diagnosis of FMD (Alexandersen et al., 2003). Antibodies to the polyproteins 3ABC are generally considered to be the most reliable indicators of FMDV infection (Mackay et al., 1997).

Immunity of FMD in animals appears to be mainly dependent on serum neutralizing antibody   levels    present   at   the   time  of

 

Microscopic examination (Thin blood film):

A small drop of fresh blood was put in the middle of one end of the slide, and spread right across the slide and then air dried. The slide was labeled using a pencil. Blood films were fixed in absolute methyl alcohol for 5 minutes, stained in 10% diluted Giemsa’s stain for 45 minutes, and washed with distilled water and then dried.

The blood films were examined microscopically under oil immersion lens for the detection of blood parasites at 10×100 magnification. The parasite identification was done with the help of keys mentioned in the book titled “Helminths, Arthropods and Protozoa of Domestic Animals” (Soulsby, 1982).

 

ELISA Test: All serum samples were tested by CHEKIT FMD-3ABC (IDEXX  Laboratories) is an indirect ELISA that detects antibodies to the FMDV 3-ABC polyprotein, according to the protocol recommended by the manufacturer instructions. Microtiter plates are supplied precoated with recombinant FMDV 3-ABC viral antigen. Dilution of the samples to be tested are incubated in the wells of these plates. Washing plates three times. A peroxidase-labeled anti-IgG conjugate was added that binds to the antibodies of the sample complexed with the 3ABC antigen. Washing plates three times, then the substrate was added to the wells. The optical density was measured at 450 nm. The diagnostic relevance of the result is obtained by comparing the optical density (OD) that develops in wells containing the samples with the OD from the wells containing the positive control.

 

 

 

Results

 

Blood smears:-

 

Microscopically Anaplasma marginale appears as spherical granules near periphery of infected red blood cells in 32 (23.19%) examined blood samples (Fig.1). Parasiteamia was ranged between (3-5%).

 

 

 

Fig. 1: Red blood cells infested with Anaplasma marginal. Giemsa stain. X=100

 

3ABC ELISA:

Nineteen out of 138 (13.76%) serum samples were positive to presence of 3-ABC-FMD antibodies. All FMD positive animals were positive to infection with Anaplasma marginal.

 

Discussion

 

The clinical sings observed in infected camels with Anaplasma marginale were in agreement with those described by (Maghaddar, 2002; Sayed, 1998 and Higgins, 1984) as paleness of mucous membranes were exhibited the development of anemia. The presence of ticks on infected camels indicated that it is the important transmitters of anaplasma sp. (Mohammed et al., 2007). Stained blood films in the current research revealed that Anaplasma marginale appears as spherical granules near periphery of infected erythrocytes, these results were similar to those shown by (Maghaddar, 2002). The positive percentage (23.19%) was in agreement with percentage in Nigeria (21.5%) where, hemoparasites (Babesia and Anaplasma)    observed     were    Anaplasma

 

livestock, mainly sheep and goats from Asia, Africa and Australia. Animals from Africa and Asia bring different FMDV serotypes which spread within the nomadic herds (Aidaros, 2002).

FMD remains the single most important animal disease, and Camelus dromedaries inhabit countries in North and East Africa, the Middle and Far East as well as in South America where FMD is endemic and the detection of antibody to non structure protein (NSP's) must indicate infection rather than vaccination (Wernery and Kaaden, 2004).

It has been reported that dromedaries can contract the disease following experimental infection and via close contact with FMD diseased livestock (Kitching, 2002). Nineteen out of the 138 (13.76%) samples were positive to presence of FMD antibodies, this result agreement with the presence of antibodies to FMDV in 39 camel sera tested in Sharkia province; Egypt (Moussa et al., 1970) and between April 2000 and July 2002, camel infected in Mongolia (Shiillegdamba et al., 2008), in addition; FMDV is present in camels even without clinical signs and camel can be a source of infection for cattle and other animals,(El Hakim, 2005).But disagree with(Wernery and Kaaden, 2004); the prevalence varied widely and that may be depending on the serologic test used in the survey (Moussa et al., 1970).

Itseems that the examined camels in our study which infected by Anaplasma marginale may become susceptible to infection by FMD and infected through close contact with FMD diseased livestock. Outbreaks of FMD repeatedly occur among cattle, sheep and goats in various regions of SaudiArabia (Hafez et al., 1993).

Camels are frequently moved across the desert inside Saudi Arabia in an area that experienced FMD outbreaks in cattle and small ruminants so camels may play a possible role in the transmission of FMDV and may carry FMDV over very long distances and across borders. Anaplasma infection is the ensuing immunosuppression that may lead to secondary infections (Grova et al.,   2011; Dumler   and   Broqui, 2004).

In conclusion; our  study  revealed  infection  of   Anaplasma  marginale  may  be   leads to 

Bukachi, S.A.; Chemuliti, J.K.and Njiru, Z.K. (2003): Constrains experienced in the introduction of camels in tsetse fly infested areas: the case of Kajiado District, Kenya. J. Camel Pract. Res. 10: 145–148.

Dumler, J.S. and Broqui, P. (2004):Molecular diagnosis of human granulocytic anaplasmosis. Expert Review of Molecular Diagnostics, 4: 89–98.

El Hakim, U.A. (2005).Foot and mouth disease in camels: role of camels in the epizootiology and transmission of foot and mouth disease in Egypt.Assiut Veterinary Medical Journal.2005; 51(107): 189-203. ISSN: 1012-5973.

Grova, L.; Olesen, I.; Steinshamn, H.; and Stuen, S. (2011):Prevalence of Anaplasma phagocytophilum infection and effect on lamb growth Grøva et al. Acta Veterinaria Scandinavica, 53:30.

Hafez, S.M.; Farag, M.A.; Mazloum, K.S. and AL Bokmy, A.M. (1993): Application of double sandwich enzyme-linked immunosorbant assay for diagnosis of foot and mouth disease   in Saudi Arabia. Dt. tierärztl. Wschr., 100:       103-106.

Higgins, A.J. (1984): The camel in health and disease: Introduction. Br. Vet. J., 140: 482-484.

Higgins, A.J. (1986): The Camel in Health and Disease. Baillaire Tindall, London, ISBN: 0-7020-1167-3.

Kocan, K.M.; de la Fuente, J.; Guglielmone, A.A.and Melen­dez, R.D. (2003): Antigens and alternatives for control of Anaplasma marginale infection incattle. Clinical Microbiology Reviews, 16: 698–712.

Kitching, P. (2002): Identification of foot and mouth disease virus carrier and subclinically infected animals and differentiation from vaccinated animals. Revue scientifique et technique. Foot and mouth disease: facing the new dilemmas. OIE 21 (3): 531 – 538.

 

 

 

 

Muneer, M.A.; Farah, I.O.; newman, J.A. and Goyal, S.M. (1988): Immunosuppression in animals. British Vet. J. 144: 289-293.

Persing, D.H. (1997): The cold zone: a curious convergence of tick transmitted diseases. Clin. Infect. Dis. 25: S35–S42.

Rabana, J.L.; Kumshe, H.A.; Kamani, J.; Hafsat, G.; Turaki, U.A.; Dilli, H.K. (2011):Effects of parasitic infections on erythrocyte indices of camels in Nigeria. Veterinary Research Forum, 2(1):        59–63.

Sarma, G.; Das, S.K. and Dutta, P.K. (1983): Outbreak of foot-andmouth disease in deer in the Assam state zoo. Vet. Rec. 113: 420- 421.

Sayed, A.S. (1998): Clinical,hematological and some tracelements status in heathy and emaciated camels in Assuit and New vally. Assuit. Vet. J., 39: 154-168.

Scott, J.M.; Pergram, R.G.; Holmes, P.H.; Pay, T.W.F.; Knight, P.A.; Jennings, F.W. and Urquahart, G.M. (1977). Immunosuppression in bovine trypanosomiasis: Field studies using foot-and-mouth disease vaccine and closteridial vaccine. Trop. Animal Health Prod. 9: 159-166.

Seri, H.; Abakarjo, A. and Didris, F. (2003): a note on camel toxoplasmosis in the sudan. 7thSci. Cong. Egyptian Society for Cattle Diseases. 7-9 Dec. 2003. Assiut, Egypt.

Sharpe, R.T. and Langley, A.M. (1983): The effect of Theileria annulata infection on the immune response of cattle to foot-and-mouth disease. British Vet. J. 139: 378-385.

Sharpe, R.T.; Langley, A.M.; Mowat, G.N.; Macaskill, J.A. and Holmes, P.H. (1982): Immunosuppression in bovine trypanosomiasis: Response of cattle infected with Trypanosoma congolense to foot-and-mouth disease vaccination and subsequent live virus challenge. Res. Vet. Sci. 32: 289-293.

 

 

 

 

 

marginale in camel (Rabana et al., 2011).

The percentage of parasitemia ranged between 3-5% that agreed with Alsaad, (2009) who found 5-11% in camels. Increase body temperature may indicate liberation of endogenous pyrogens due to cellular lyses stimulating thermoregulatory centers of the hypothalamus (Higgin, 1986). The cause of anemia during blood parasitic infection may be multifactorial, due to the direct effect of the parasite to the infected erythrocytes or decrease the life span of RBCs and or suppression of hemopoitic system (Mahran, 2004).

FMD is also of great importance to Camelus dromedaries, because the disease is endemic in many countries, where Camelus dromedaries are reared. Saudi Arabia, with a dromedary population of nearly one million, annually imports approximately   6.5 million

 

increase susceptibility of camels to infection with FMDV. It would be of great interest to know if dromedaries play a role in transmitting the FMDVs, in addition; further studies are required to evaluate the possible immunosuppression role of Anaplasma marginale to FMDVs infections in camels. Application of vaccination program for camel populations against FMD in KSA is recommended to avoid the spread of FMDV by carrier camels which live mostly in contact with other susceptible animals.

 

ACKNOWLEDGEMENTS

 

We  would like to thank Professor Dr. S.S.A. Sharawi, Professor of Virology, Faculty of Veterinary Medicine, BanhaUniversity.

 

References

 

Ahmad, N.; Bansal, S.R.; Gupta, S.L.; Sharma, R.D. and Sharma, R. (1991): Suppressed immune response to foot-and-mouth disease vaccination in guinea pigs experimentally infected with Trypanosoma evansi. Indian Vet. J. 68: 622-626.

Aidaros, H.A. (2002): Regional status and approaches to control and eradication of foot and mouth disease in the Middle East and North Africa. Revue Scientifique et Technique de l_Office Internationaldes Epizooties 21:         451–458.

Alexandersen, S.; Zhang, Z.; Donaldson, A.I. and Garland, A.J. (2003): Pathogenesis and diagnosis of foot-and-mouth disease. J. Comp. Pathol., 129(1): 1-36.

Alsaad, K.M. (2009): Clinical, Hematological and Biochemical Studies of Anaplasmosis in Arabian One-Humped Camels (Camelus dromedaries). J. Anim. Vet. Adv., 8: 1794-1797.

Bikaner Website (2008): Online Article on Camel, National Research Center on Camel, Jorbeer, Bikaner (Rajasthan) India.

 

 

Kocan, K.M.; Blouin, E.F.; Barbet, A.F. (2000): Anaplasmosis control: past, present and future. Ann. N. Y. Acad. Sci., 916: 501-509.

Larska, M.; Wernery, U.; Kinne, J.; Schuster, R.; Alexandersen, G. and Alexandersen, S. (2008): Differences in the susceptibility of dromedary and Bactrian camels to foot-and-mouth disease virus. Epidemiol. Infect., 2008 Aug. 8: 1–6. [Epub ahead of print].

Mackay, D.K.J.; Forsyth, M.A.; Davies, P.R.; Berlinzani, A.; Belsham, G.J.; Flint, M. and Ryan, M.D. (1997): Differentiating infection from vaccination in foot-and-mouth disease using a panel of recombinant, nonstructural proteins in ELISA. Vaccine, 16: 446–459.

Maghaddar, N. (2002):Occurance of Anaplasma marginale in camels of Shiraz. Proceedings of the 3rd Iranian Veterinary Clinicians Conference, Oct. 29-31, ShirazUniversity, Mashhad, pp: 35-38.

Mahran, O.M. (2004): Some studies on blood parasite in camels (Camelus dromedaries) at Shalatin city, Red Sea Governorate. Assiut Vet. J., 50: 172-183.

Marchette, N. and Stiller, D. (1982): The Anaplasmataceae, Bartonellaceae, and Rochalimaea quintana. In: Marchette, N.J. (Ed.), Ecological Relationships and Evolution in the Rickettsiae. CRC Press, Boca Raton, Florida, USA, p.98-106.

Mohammed, A.K.; Sackey, A.K.B.; Tekdek, L.B. and Gefu, J.O. (2007): Common health problems of the one humped camel (Camelus dromedarius) introduced into sub-humid climate in Zaria, Nigeria. Res. J. Anim. Sci. 1:   1–5.

Moussa, A.A.; Nasser, M. and Mowafi, L.E. (1970): Occurrence of foot-and-mouth disease in different species of animals at Sharkia province. J. Egypt Vet. Med. Assoc. 40: 23-35.

 

 

 

 

 

Shiilegdamba, E.; Carpenter, T.E.; Perez, A.M.   and   Thurmond,   M.C.    (2008):

Temporal-spatial epidemiology of foot-and-mouth disease outbreaks in Mongolia, 2000 - 2002.Veterinary Research Communications. 2008 Mar; 32(3): 201-207. ISSN: 0165-7380.

Smith, B.P. (1996): Large Animal Internal Medicine. 2nd Edn., Mosby Year Book. Inc., New. York, pp: 1214-1217.

Somsak, T. (2004):Diagnostic test of foot and mouth disease.Royal Gazette Vol. 121 Section 120D.

Soulsby, E.J.L. (1982): Helminths, Arthropods and Protozoa of Domestic Animals. Protozoa; Genera Anaplasma. 7th Ed. Lea & Febiger Philadelphia, Great Britain, p.752-753.

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Wernery, U. and Kaaden, O.R. (2004): Foot-and-mouth disease in camelids: a review. The Veterinary Journal (168), Issue 2: 134-142.

Wernery, U.; Ul-Haq, A.; Joseph, M. and Kinne, J. (2004): Tetanus in a camel (Camelus dromedarius): a case report. Trop. Anim. Health Prod. 36: 217–224.

 

 

References
 
Ahmad, N.; Bansal, S.R.; Gupta, S.L.; Sharma, R.D. and Sharma, R. (1991): Suppressed immune response to foot-and-mouth disease vaccination in guinea pigs experimentally infected with Trypanosoma evansi. Indian Vet. J. 68: 622-626.
Aidaros, H.A. (2002): Regional status and approaches to control and eradication of foot and mouth disease in the Middle East and North Africa. Revue Scientifique et Technique de l_Office Internationaldes Epizooties 21:         451–458.
Alexandersen, S.; Zhang, Z.; Donaldson, A.I. and Garland, A.J. (2003): Pathogenesis and diagnosis of foot-and-mouth disease. J. Comp. Pathol., 129(1): 1-36.
Alsaad, K.M. (2009): Clinical, Hematological and Biochemical Studies of Anaplasmosis in Arabian One-Humped Camels (Camelus dromedaries). J. Anim. Vet. Adv., 8: 1794-1797.
Bikaner Website (2008): Online Article on Camel, National Research Center on Camel, Jorbeer, Bikaner (Rajasthan) India.
 
 
Kocan, K.M.; Blouin, E.F.; Barbet, A.F. (2000): Anaplasmosis control: past, present and future. Ann. N. Y. Acad. Sci., 916: 501-509.
Larska, M.; Wernery, U.; Kinne, J.; Schuster, R.; Alexandersen, G. and Alexandersen, S. (2008): Differences in the susceptibility of dromedary and Bactrian camels to foot-and-mouth disease virus. Epidemiol. Infect., 2008 Aug. 8: 1–6. [Epub ahead of print].
Mackay, D.K.J.; Forsyth, M.A.; Davies, P.R.; Berlinzani, A.; Belsham, G.J.; Flint, M. and Ryan, M.D. (1997): Differentiating infection from vaccination in foot-and-mouth disease using a panel of recombinant, nonstructural proteins in ELISA. Vaccine, 16: 446–459.
Maghaddar, N. (2002):Occurance of Anaplasma marginale in camels of Shiraz. Proceedings of the 3rd Iranian Veterinary Clinicians Conference, Oct. 29-31, ShirazUniversity, Mashhad, pp: 35-38.
Mahran, O.M. (2004): Some studies on blood parasite in camels (Camelus dromedaries) at Shalatin city, Red Sea Governorate. Assiut Vet. J., 50: 172-183.
Marchette, N. and Stiller, D. (1982): The Anaplasmataceae, Bartonellaceae, and Rochalimaea quintana. In: Marchette, N.J. (Ed.), Ecological Relationships and Evolution in the Rickettsiae. CRC Press, Boca Raton, Florida, USA, p.98-106.
Mohammed, A.K.; Sackey, A.K.B.; Tekdek, L.B. and Gefu, J.O. (2007): Common health problems of the one humped camel (Camelus dromedarius) introduced into sub-humid climate in Zaria, Nigeria. Res. J. Anim. Sci. 1:   1–5.
Moussa, A.A.; Nasser, M. and Mowafi, L.E. (1970): Occurrence of foot-and-mouth disease in different species of animals at Sharkia province. J. Egypt Vet. Med. Assoc. 40: 23-35.
 
 
 
 
 
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