Brucellosis in a Camel Herd: The Role of Missed Vaccination and Illegal Imports

Document Type : Original Article

Authors

1 Department of Basic Sciences, Faculty of Veterinary Medicine, Ardakan University, P.O. Box 184, Ardakan, Iran

2 Department of Clinical Sciences, Faculty of Veterinary Medicine, Ardakan University, P.O. Box 184, Ardakan, Iran.

Abstract

This study aimed to detect the presence of Brucella spp. DNA in aborted camel fetuses from a dairy herd in Meybod, Yazd Province, Iran, using genus-specific PCR. The broader objective was to assess the epidemiological importance of camel brucellosis in a region with limited surveillance and no targeted vaccination programs for camels. A total of 50 aborted fetuses from a single Camelus dromedarius herd were examined. Fetal abomasal contents were collected and tested using Modified Ziehl-Neelsen staining, followed by molecular confirmation via polymerase chain reaction (PCR) targeting the IS711 gene of Brucella spp. DNA was extracted using a commercial tissue DNA kit, and PCR conditions were optimized for specificity. Positive and negative controls were included in each PCR run to ensure reliability and prevent contamination. Modified Ziehl-Neelsen staining revealed Brucella-like organisms in 82% (41/50) of the samples. PCR confirmed the presence of Brucella DNA in 92% (46/50) of the fetal tissues, indicating a high prevalence of infection in the herd. While 72% of the samples tested positive in both Modified Ziehl-Neelsen staining and PCR assays, 2% were negative by Modified Ziehl-Neelsen staining but positive by PCR. This study reveals an unusually high rate of Brucella spp. in aborted fetuses from a single camel herd, suggesting an active outbreak likely exacerbated by illegal livestock movement and lack of camel surveillance. Molecular detection confirms infection, although species-level identification was not performed. These findings highlight the urgent need for targeted camel vaccination, enhanced molecular surveillance, and stricter control over cross-border animal trade.

Keywords

References

  1. Gwida MM, El-Gohary AH, Melzer F, Tomaso H, Rösler U, Wernery U, et al. Comparison of diagnostic tests for the detection of Brucella spp. in camel sera. BMC Res Notes. 2011 Dec 6;4:525.
  2. Wernery U. Camelid brucellosis: a review. Rev Sci Tech Int Off Epizoot. 2014 Dec;33(3):839–57.
  3. Radwan AI, Bekairi SI, Prasad PV. Serological and bacteriological study of brucellosis in camels in central Saudi Arabia. Rev Sci Tech Int Off Epizoot. 1992 Sep;11(3):837–44.
  4. Díaz Aparicio E. Epidemiology of brucellosis in domestic animals caused by Brucella melitensis, Brucella suis and Brucella abortus. Rev Sci Tech Int Off Epizoot. 2013 Apr;32(1):43–51, 53–60.
  5. World Health Organization; Food and Agriculture Organization of the United Nations; World Organisation for Animal Health. Brucellosis in Humans and Animals [Internet]. 2006 Jun [cited 2025 Jun 20]. Report No.: WHO/CDS/EPR/2006.7. Available from: https://www.who.int/publications/i/item/9789241547130
  6. Golshani M, Buozari S. A review of Brucellosis in Iran: Epidemiology, Risk Factors, Diagnosis, Control, and Prevention. Iran Biomed J. 2017 Nov;21(6):349–59.
  7. Franco MP, Mulder M, Gilman RH, Smits HL. Human brucellosis. Lancet Infect Dis. 2007 Dec;7(12):775–86.
  8. Musallam II, Abo-Shehada MN, Hegazy YM, Holt HR, Guitian FJ. Systematic review of brucellosis in the Middle East: disease frequency in ruminants and humans and risk factors for human infection. Epidemiol Infect. 2016 Mar;144(4):671–85.
  9. Sohrabi A, Hajia M. Brucellosis: The Current Situation in Iran and Neighboring Countries. Infect Disord Drug Targets. 2020;20(5):763–4.
  10. Esmaeil Zowghi, Abdollah Ebadi, Mehran Yarahmadi. Isolation and Identification of Brucella Organisms in Iran. Iran J Clin Infect Dis. 2008;3(4):185–8.
  11. Alton GG, Jones LM, Angus R, Verger JM. Techniques for the Brucellosis Laboratory. In 1988. Available from: https://api.semanticscholar.org/CorpusID:70801215
  12. World Organisation for Animal Health. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, thirteenth edition 2024.
  13. Abdel-Hamid NH, Beleta EIM, Kelany MA, Ismail RI, Shalaby NA, Khafagi MHM. Validation of real-time polymerase chain reaction versus conventional polymerase chain reaction for diagnosis of brucellosis in cattle sera. Vet World. 2021 Jan;14(1):144–54.
  14. Mitka S, Anetakis C, Souliou E, Diza E, Kansouzidou A. Evaluation of different PCR assays for early detection of acute and relapsing brucellosis in humans in comparison with conventional methods. J Clin Microbiol. 2007 Apr;45(4):1211–8.
  15. Hinić V, Brodard I, Thomann A, Cvetnić Z, Makaya PV, Frey J, et al. Novel identification and differentiation of Brucella melitensis, B. abortus, B. suis, B. ovis, B. canis, and B. neotomae suitable for both conventional and real-time PCR systems. J Microbiol Methods. 2008 Oct;75(2):375–8.
  16. Nabavi M, Hatami H, Jamaliarand H. Epidemiological, Risk Factors, Clinical, and Laboratory Features of Brucellosis in the Southwest of Iran within 2009-2015. Int J Prev Med. 2019;10:108.
  17. Khoshnood S, Pakzad R, Koupaei M, Shirani M, Araghi A, Irani GM, et al. Prevalence, diagnosis, and manifestations of brucellosis: A systematic review and meta-analysis. Front Vet Sci. 2022;9:976215.
  18. Behzadifar M, Shahabi S, Zeinali M, Ghanbari MK, Martini M, Bragazzi NL. A policy analysis of agenda-setting of Brucellosis in Iran using a multiple-stream framework: health policy and historical implications. J Prev Med Hyg. 2021 Jun;62(2):E544–51.
  19. Holt HR, Eltholth MM, Hegazy YM, El-Tras WF, Tayel AA, Guitian J. Brucella spp. infection in large ruminants in an endemic area of Egypt: cross-sectional study investigating seroprevalence, risk factors and livestock owner’s knowledge, attitudes and practices (KAPs). BMC Public Health. 2011 May 19;11:341.
  20. Gwida M, Al Dahouk S, Melzer F, Rösler U, Neubauer H, Tomaso H. Brucellosis - regionally emerging zoonotic disease? Croat Med J. 2010 Aug;51(4):289–95.
  21. Alirezaei A, Khalili M, Baseri N, Esmaeili S, Mohammadi Damaneh E, Kazeminia S. Molecular detection of Brucella species among aborted small ruminants in southeast Iran. Braz J Microbiol Publ Braz Soc Microbiol. 2024 Mar;55(1):911–7.
  22. Rafieipour A, Ziaei N. Study of brucellosis in serum of camels in southeast of Iran. Vet Sci Dev. 2011 Dec;1:14.
  23. Khalafalla A, Eknah MMA, Abdelaziz M, Ghoneim I. A study on some reproductive disorders in dromedary camel herds in Saudi Arabia with special references to uterine infections and abortion. Trop Anim Health Prod. 2017;49:967–74.
  24. Abu Damir H, Tageldin MH, Kenyon SJ, Idris OF. Isolation of Brucella abortus from experimentally infected dromedary camels in Sudan: a preliminary report. Vet Res Commun. 1989;13(6):403–6.
  25. Principles of Epidemiology | Lesson 1 - Section 11 [Internet]. 2023 [cited 2025 Sep 16]. Available from: https://archive.cdc.gov/www_cdc_gov/csels/dsepd/ss1978/lesson1/section11.html
  26. Thrusfield M, Christley R, Brown H, Diggle PJ, French N, Howe K, et al. Veterinary Epidemiology [Internet]. Hoboken, NJ: John Wiley & Sons Ltd; 2018. Available from: https://doi.org/10.1002/9781118280249
  27. Refai M. Incidence and control of brucellosis in the Near East region. Vet Microbiol. 2002 Dec 20;90(1–4):81–110.
  28. FAO, WOAH. Transboundary Animal Disease Risks and Camel Movement Across South Asia. Rome: Food and Agriculture Organization of the United Nations; 2021. (FAO Animal Production and Health Report).
  29. Jamali MK, Yousaf A, Sarki I, Babar A, Sharna SN. Assessments of Prevalence of Brucellosis in Camels Through the Contrast of Serological Assessments in South Punjab, Pakistan. Am J Zool. 2021;4(4):65–8.
  30. Shahzad A, Khan A, Khan M, Saqib M. Seroprevalence and molecular investigation of brucellosis in camels of selected districts of Punjab, Pakistan. Thai Vet Med. 2017 Jun;47:207.
  31. Shabbir MZ, Sohail T, Ul-Rahman A, Abbas T, Ali Q, Rehman ZU, et al. Sentinel surveillance of selected veterinary and public health pathogens in camel population originating from Southern Punjab province, Pakistan. Acta Trop. 2020 May;205:105435.
  32. Faye B, Bengoumi M. Camel Clinical Biochemistry and Hematology. Camel Clinical Biochemistry and Hematology. 2018.
  33. Whatmore A, Perrett LL, MacMillan AP. Characterisation of the genetic diversity of Brucella by multilocus sequencing. BMC Microbiol. 2007;7:34–34.
  34. Scholz HC, Nöckler K. Brucella molecular epidemiology and typing. In: Clifton NJ, editor. Methods in Molecular Biology [Internet]. New York, NY: Springer; 2015. p. 299–321. Available from: https://doi.org/10.1007/978-1-4939-2963-4_20
Veterinary and Comparative Biomedical Research
Volume 2, Issue 2
December 2025
Pages 75-81

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