The diseases are one of the major problelms faced in goat farming which are responsible for significant economic losses to the farmers
(Mahdi et al., 2015; Doley and Nekibuddin, 2017). Amongst the diseases, genital abnormalities are the important ones that adversely affect reproductive potential of the goats
(Azawi et al., 2010). The important reproductive aliments in goats are abortion, retention of placenta and stillbirth
(Beena et al., 2017). Out of the aliments mentioned above, abortion is the commonest one, which affects productivity profoundly in goats and sheep (
Menzies, 2011).
Both infectious and non-infectious agents may cause abortion in goats
(Entrican et al., 2009), but infectious ones are the predominant cause of caprine abortions (
Smith and Sherman, 2009). Further, caprine abortion is mainly caused by the bacterial pathogens amongst the infectious agents (
Smith and Sherman, 2009;
Kahn and Line, 2010). There are several viruses such as Akabane, Cache Valley, Blue Tongue, Border Disease, Herpes, Nairobi Sheep Disease, PPR, Rift Valley Fever, Wesselsbron Disease, Bovine Viral Diarrhoea,
etc, which are capable to cause abortions in goats (
Smith and Sherman, 2009) and caprine herpes virus is the most common one in causing abortions in goats (
Moeller, 2001;
Kahn and Line, 2010). Under the parasitic agents,
Toxoplasma gondii,
Neospora caninum,
Sarcocystis,
Anaplasma, etc. may cause caprine abortions and the most common one is
Toxoplasma gondii (
Shaapan, 2016). The fungal agents associated with caprine abortions are
Aspergillus,
Candida,
Mucor,
Rhizopus,
Penicillium,
Cladosporium,
Rhodotorula,
Absidia,
Alternaria,
Fusarium,
etc.
(Pal et al., 1985; Pal, 1988;
Verma et al., 1999). Aspergillus followed by
Candida is the most prevalent fungi associated with abortion in goats (
Vandyousefi and Zoghi, 1988).
Brucella,
Chlamydia,
Coxiella burnetii,
Campylobacter,
Listeria monocytogenes,
Leptospira (mostly interrogans, grippotyphosa and pomona),
Mycoplasma,
Salmonella,
E. coli,
S. aureus,
Pseudomonas aeruginosa,
Streptococcus,
Aeromonas,
Fusobacterium,
Trueperella pyogenes, etc. are the main causative agents of caprine abortions under Bacteria, Rickettsia and Chlamydia (
Menzies, 2011,
Elhaig et al., 2018; Tejedor-Junco et al., 2019) and the most common ones are
Brucella melitensis,
Chlamydophila,
Coxiella burnetii, Campylobacter and
Listeria monocytogenes (Menzies, 2011;
Kushwaha et al., 2016; Saini et al., 2017; Rossetti et al., 2017; Rajagunalan et al., 2019; Lakshmikanth et al., 2021). These microorganisms are also capable to cause infections/diseases in human beings
(Kumar et al., 2010; Mändar et al., 2015). The presence of the above microorganisms in the genital tract of the male goat may cause deterioration of semen quality leading to reduced sperm motility and viability (Gangwar
et al., 2020) and may spread the infection to female goats through natural service as well as artificial insemination (
Mändar et al., 2015). Likewise, the presence of the said microorganisms in the female genital tracts may cause abortion and infertility in goats and simultaneously, may infect male goats and humans as well
(Gangwar et al., 2020). That is why, the current study was undertaken to assess the association of
Brucella melitensis, Chlamydophila spp.,
Campylobacter spp.,
Brucella abortus and
Coxiella burnetii with caprine abortions.
The study was conducted during the year 2020-2021 at ICAR-Central Institute for Research on Goats (ICAR-CIRG), Makhdoom, Farah, Mathura, Uttar Pradesh (India).
Sample collection
A total of 260 biological samples (number of preputial secretions=230, number of vaginal secretions=15 and foetal stomach content=15) were aseptically collected and immediately transported to the Microbiology Laboratory of ICAR-CIRG for further investigation. The samples were comprised of vaginal and preputial secretions of goats and stomach contents from the aborted foetuses. The goats reared at ICAR-CIRG and the field goats of Districts Agra and Mathura of Uttar Pradesh and Bharatpur of Rajasthan (India) were selected for the experimentation.
Extraction of the genomic DNAs
The genomic DNA extraction from the biological samples was done by using DNASure ® Tissue Mini Kit (Genetix Asia Pvt Ltd) according to the protocol of the manufacturer. The extracted DNAs were run in a 0.8% agarose gel to determine their presence and integrity.
Molecular identification of the microorganisms
The detection of the targeted infectious agents (
Brucella melitensis,
Brucella abortus,
Coxiella burnetii,
Chlamydophila spp. and
Campylobacter spp.) in the biological samples (vaginal/preputial secretions and foetal stomach contents) was done by specific polymerase chain reactions (PCRs; species and genus-specific). Standardization of PCRs was done using gradient PCR. Details regarding the primers, target genes and size of PCR products are given in Table 1. Likewise, the details regarding the PCR conditions are given in Table 2. The PCRs were performed by using EmeraldAmp GT PCR Master Mix (DSS Takara) following the manufacturer’s instructions. The PCR products were run in a 1.5% TAE-agarose gel with a 100 bp marker (Thermo Scientific) to determine the gene size.
Out of 260 samples, the presence of
Coxiella burnetii was not detected in any sample (Table 3; Fig 1). Thus, in our study, the role of
Coxiella burnetii in causing an abortion in goats was not proven in the sampling area. But,
Vaidya et al., (2010) demonstrated the prevalence of Q fever in goats as 6.1% after screening a total of 53 samples (genital swabs, milk, fecal swabs, urine and serum).
Rajagunalan et al., 2019 reported the first case of abortion induced by
Coxiella burnetii in goats in India.
Brucella abortus was detected in the vaginal secretions of two aborted goats, whereas presence of
Brucella melitensis, Campylobacter spp.,
Chlamydophila spp.
and Coxiella burnetii in these goats was not confirmed, which indicates the potential of
Brucella abortus to cause abortion in goats too (Table 3; Fig 2). This is the unique finding of this study. However,
Moeller (2001) also reported that caprine abortion occurred due to
Brucella abortus.
Only 10 samples out of 260 (6 vaginal swabs from the aborted goats and 4 fetal stomach contents) were found positive for
Brucella melitensis (Table 3; Fig 3), whereas
Brucella melitensis, Brucella abortus, Campylobacter spp.,
Chlamydophila spp. and
Coxiella burnetii were not detected in these goats. However, many other workers reported a higher prevalence of
B. melitensis in genital tracts of goats as well as the main cause of caprine abortions (
Smith and Sherman, 2009;
Kahn and Line, 2010;
Samadi et al., 2010; Sadhu et al., 2015). Hence, further study is required to evaluate the current finding about role of
Brucella melitensis in caprine abortion.
A total of 117 samples were found positive for
Chlamydophila spp. (110 preputial secretions and 7 stomach contents) (Table 3; Fig 4), whereas 84 were found positive for
Campylobacter spp. (all preputial secretions) (Table 3; Fig 5). A total of 63 samples were found positive for both
Chlamydophila spp. and
Campylobacter spp. These two microorganisms, being commensals, can act as opportunistic pathogens and their pathological significance needs to be associated with the gross and histopathological changes in the affected animals.
Gangwar et al., (2020) found 53.13% of samples positive for
Chlamydophila spp. and
Sharma et al., (2008) also found
Chlamydophila spp. as the most common cause of abortions in goats and sheep. However, contrary to our finding, in a study conducted by
Beena et al., (2017), 5.30% positivity of
Campylobacter spp. was reported in the genital samples from goats, whereas in another study, campylobacteriosis was reported only rarely as a cause of abortion in goats (
Moeller, 2001).
Thus, the present study concludes that
Chlamydophila spp. and
Campylobacter spp. were found as the prevalent microbial agents, which may be associated with abortion in goats in adverse conditions during the forthcoming pregnancies.
