Serological, cultural and molecular evidence of Brucella melitensis infection in goats in Al Jabal Al Akhdar, Sultanate of Oman

Abstract

Brucellosis, one of the most common zoonotic diseases and has significant public health and economic importance worldwide. Few studies and reports have been performed to estimate the true prevalence of animal brucellosis in the Sultanate of Oman; however, no incidence of the disease was previously reported in Al Jabal Al Akhdar. The purpose of this study was to investigate the prevalence of brucellosis in goats in eight villages in Al Jebal Al Akhdar, Sultanate of Oman, namely: Al Aqaieb, Al Helailat, Al Ghilayil, Hail Al Hedap, Da'an Al Hamra, Shnoot, Al Qasha'e and Al Sarah, Al Jabal Al Akhdar in the Sultanate of Oman. In this study we used different diagnostic serological tests, namely, RBT, I‐ELISA and CFT to study the prevalence of Brucella infection in goats in Al Jabal Al Akhdar. Statistical analysis using Kappa statistics was used to compare the performance of the serological tests. Biochemical tests and species‐specific Multiplex PCR were used to identify the brucella species involved in the infection. A structured questionnaire and Chi‐square (x2) statistical analysis was used to identify related brucellosis risk factors. This study is the first to reveal brucellosis infection in goats in eight villages in Al Jebal Al Akhdar, Sultanate of Oman, namely: Al Aqaieb, Al Helailat, Al Ghilayil, Hail Al Hedap, Da'an Al Hamra, Shnoot, Al Qasha'e and Al Sarah, with an overall seroprevalence of 11.1%. The study also compared the performance of three different serological tests, namely, RBT, I‐ELISA and CFT. Statistical analysis using Kappa statistics showed that the degree of agreement was best seen between RBT and CFT (96%), followed by RBT, I‐ ELISA (91.4%) and CFT and I‐ ELISA (89.2%). Biochemical tests and species‐specific Multiplex PCR showed the typical profile for B. melitensis. A structured questionnaire and Chi‐square (x2) statistical analysis indicated that the presence of abortion is the major risk factor for the prevalence of brucellosis, whereas age and sex were not significant factors in the tested animals. Besides, poor knowledge about brucellosis, consumption of unpasteurized milk or milk products, free trade of animals and the introduction of new animal breeds to herds were all contributing risk factors to the prevalence of brucellosis. The prevalence of human brucellosis obtained verbally from pastoralists gave an insight that brucellosis could pose a public health hazard, especially in those high‐risk groups, mainly the pastoralists in the study area. Because of their constant and increasing interaction with their animals, pastoralists could be at a high risk of occupational infection.

Epidemiological features of human brucellosis in Tongliao City, Inner Mongolia province, China: a cross-sectional study over an 11-year period (2007–2017)

“…First, the data were collected through passive public health surveillance. With regard to the untypical symptoms of some human brucellosis and inaccessible health facilities for some patients, data may be influenced by under-reporting, laboratory misdiagnosis and incomplete information 29 30. Second, as human brucellosis is a zoonotic disease which is affected by many factors, such as the density of livestock, meat yield, slaughter amount and environment, a dynamic model including the abovementioned factors needs to be taken into account for brucellosis transmission and prediction, but these data could not be obtained in the present study.…”

Seroprevalence of brucellosis in sheep and goats in the Arabian Gulf region

“…The overall brucellosis prevalence seropositivity in the study area was 0.48% by RBT and i-ELISA, which is lower than that found in Al-Ahsa KSA which was 1.1% [ 41 ], Alkamil, KSA 5.88% [ 10 ], Abu Dhabi Emirate 8.3% [ 42 ], Oman 2.4%, (Dhofar) 8.6%, Northern governorates 0.97%, Al Aqaieb 24%, and Al Helailat 40%. While in Al Ghilayil, Al Qasha’e, Da’anAlhamra, Al Sarah, Hail Al Hedap, and Shnoot are free from brucellosis [ 13 , 43 ].…”

“…Secondary can refer acidified antigens in RPBT usually produce prozoning phenomena (false positive result), [ 44 ]. Hence, i- ELISA has been evaluated for many years for their better sensitivity to detect anti- Brucella antibodies in all species especially small ruminant, several studies reported that i-ELISA is more sensitive than conventional tests [ 13 ] assessed the indirect ELISA efficacy in comparison with CFT and RBPT on sera from B. melitensis infected ewes. Indirect ELISA can be a useful screening tool and could be used alone or in addition to RBT.…”

Zoonotic Diseases in Oman: Successes, Challenges, and Future Directions

“…Brucellosis is the most common zoonotic disease in Oman (Idris et al, 1993, El-Amin et al, 2001, MOH, Oman, 2014, Ministry of Health, Oman, 2017. Brucella melitensis is widely circulated in camels, goats, sheep, and cattle in Oman [MOH, Oman, 2017;El Tahir and Nair, 2011;El Tahir et al, 2018; National center for Statistics and information). Nationally, the brucellosis incidence rate declined from 20/ 100,000 population (371 cases) in 1992 to 8/100,000 population (376 cases) in 2017 (Table 1).…”

“…Eighty percent (1145) of the cases were male. Sixty-three percent (908) of the cases occurred due to ingestion of unpasteurized milk or fresh unpasteurized cheese from infected goats or sheep, while 83% had a history of direct contact with animals, mainly cattle (MOH, 2014;El-Amin et al, 2001;Idris et al, 1993;El Tahir and Nair, 2011;El Tahir et al, 2018; National center for Statistics and information; Al-Rawahi, 2015).…”