Paralytic rabies in a goat

Abstract

BackgroundParalytic form of rabies is frequent in cattle in Latin America, but it is uncommon in goats. There are few clinical reports on furious rabies affecting goats, and the sporadic cases of rabid goats from surveillance programs worldwide lack clinical data. Furthermore, few studies reported the cerebrospinal fluid findings in rabid livestock.Case presentationOn a farm in Midwestern Brazil, six of 47 Saanen goats died within one week. No vaccination protocols were implemented on the farm and the owner stated bat bites history on the livestock. Although rabies is endemic in Brazil, livestock vaccination is not mandatory. One 1-year-old buck was evaluated and showed non-specific clinical signs evolving within 12-h to nervous signs. Cerebrospinal fluid analysis revealed mononuclear pleocytosis, hyperproteinemia and high glucose levels. At necropsy, no gross lesions were present. Microscopically, discrete to moderate perivascular lymphoplasmacytic cuffing in gray and white matter, neuronal necrosis, neuronophagia, and mononuclear ganglioneuritis was observed in the brainstem and cervical spinal cord. Immunohistochemistry revealed strong anti-rabies virus immunostaining. Fresh central nervous system samples were positive for rabies in direct fluorescent antibody test (dFAT) and mouse intracerebral inoculation test (MIT). Exposed livestock recommendations included immediate vaccination, a strict isolation period of 90 days, and booster vaccinations during the third and eighth weeks.ConclusionIHC revealed the widespread distribution of rabies virus antigen in the goat’s CNS, contrasting the discrete pathological changes. In this goat, definitive diagnosis of paralytic rabies was obtained through the association of epidemiological, clinical, laboratorial, pathological findings (histology and IHC) and gold standard confirmatory tests (dFAT and MIT).

Cerebrospinal fluid analysis in 58 ruminants showing neurological disorders

“…A conclusive diagnosis of rabies was obtained by histology (Negri's bodies inclusions), immunohistochemistry, or gold-standard methods. Rabies is a viral disease with important zoonotic potential and high lethality (Moreira et al 2018). In our cases, CSF analysis revealed pleocytosis in 6 of 11 ruminants (54.5%), with counts of 16-333 leukocytes/µL, mainly involving mononuclear cells.…”

“…Eleven cases (18.9%) of rabies were diagnosed, including one goat (Case 1) and 10 cattle (Cases 2-11). In all rabies cases, the common epidemiological background was the absence of preventive vaccination and the presence of hematophagous bats on the farms (Moreira et al 2018). A conclusive diagnosis of rabies was obtained by histology (Negri's bodies inclusions), immunohistochemistry, or gold-standard methods.…”

“…The other five ruminants (45.5%) had no CSF changes (leukocytes counts peaked 6/µL). Despite few reports on CSF findings in rabid ruminants, when mononuclear pleocytosis (mainly lymphocytic) is present, CSF analysis presents as an important ancillary tool for diagnosis and allows exclusion of potential CNS bacterial infections that cause similar neurological signs (Moreira et al 2018), since this finding is typically associated to viral infections (Stokol et al 2009). Recently, a study evaluating 17 rabid cattle concluded that CSF may not change or may exhibit discrete mononuclear pleocytosis and/or mildly elevated protein within the CSF (Queiroz et al 2018).…”

“…We reinforce rabies zoonotic potential, and suspected cases should be isolated and contact kept to a minimum with only vaccinated humans. Gloves and masks should be worn during examination, samples collection or when performing necropsies (Moreira et al 2018). Two sporadic cases of meningoencephalitis caused by bovine herpesvirus 5 (BoHV-5) (Cases 12 and 13) were identified in two 1-year-old Nelore steers.…”

“…Despite its importance as a tool to aid diagnosis, data regarding CSF examinations in spontaneous cases of CNS diseases in ruminants from Brazil are limited (Lisbôa et al 1996, Della Libera et al 2004, Câmara et al 2009, 2014a, 2014b, 2014c, Queiroz et al 2018, Moreira et al 2018, and most reports involve experimental studies (Lisbôa et al 2009, Cunha et al 2011, Isernhagen et al 2011. Therefore, this study aimed to report the results of CSF analysis in 58 ruminants showing signs of neurological disorders.…”