Virology Bovine RNA

Rabies Virus Type

Rhabdoviridae

Rabies Epidemiology

wildlife reservoirs (bats, skunks, coons) maintain virus in many areas

worldwide distribution but some regions have more controlled rabies programs

Rabies Symptoms

Behavioral Changes: execessive salivation, confusion, aggression (rare)

Neuro signs: ataxia, paralysis, difficulty swallowing, abnormal vocalization

progression: rapid deterioration, coma, and death once clinical signs appear

Rabies Transmission

typically via saliva from infected animals

bite wounds introdcue virus into tissues

Rabies Incubation Period

highly variable (weeks to months) depending on bite site and viral dose

Rabies Diagnosis

Ante-mortem: challenging, clinical suspicion, history of exposure

Post-mortem: direct flourescent antibody test on brain tissue

differentials: other neuro diseases

Vesicular Stomatitis Virus Type

Rhabdovirade

Vesicular Stomatitis Transmission

insect vectors (black flies, sand flies)

direct contact with infected animals or contaminated surfaces

Vesicular Stomatitis Epidemiology

occurs sporadically in the Americas, more common in Mexico

outbreaks can cause significant economic losses

Vesicular Stomatitis Symptoms

vesicles and erosions in mouth, tongue, feet, teats

salivation, lameness, decreased milk production

reportable disease - similar to foot and mouth disease but typically less severe

Bovine leukosis virus Virus Type

retrovirus

Bovine leukosis virus characterized by what

reverse transcriptase allowing for lifelong persistence of virus within infected animal

Bovine leukosis virus Transmission

primarily through transfer of infected cells such as contaminated needles, surgical instruments, or colostrum/milk

horizontal transmission can also occur

Bovine leukosis virus Treatment, Control, and Prevention

diligent biosecurity measures, like proper needle hygiene, single-use gloves, and management of colostrum

Bovine leukosis virus Symptoms

most infections are subclinical: most remain asymptomatic their entire lives

Persistent lymphocytosis: increased lymphocytes in blood

Lymphosarcoma: most common clinical manifestation

enlarged lymph nodes with internal organ involvement: in some cases spinal cord can be affected leading to neuro signs

Rotavirus Virus Type

reoviridae

Rotavirus epidemiology

affects young calves, high morbidity, variable mortality

Rotavirus features

stable in the environment

infects and damages enteroctyes in SI

Rotavirus transmission

fecal-oral, virus shed in feces

Rotavirus symptoms

profuse, watery diarrhea in calves

dehydration, weakness

reduced milk intake and growth

Rotavirus Treatment, Control, and Prevention

good colostrum managment

vaccinate pregnant dams

hygiene and biosecurity

Bluetongue Virus Type

reoviridae

Bluetongue Transmission

primarily by culicoides midges

Bluetongue host range

commonly affects sheep but can infect cattle and other ruminants

Bluetongue Symptoms

often mild or subclinical

occasional lesions: oral erosions, nasal discharge, salivation

rarely: lameness, coronitis, decreased milk production

Bluetonge Treatment, Control, and Prevention

vector control: reduce midge breeding sites, insecticides

vaccination: in regions where vaccines are available and serotypes are known

surveillance

Bovine Coronavirus Virus Type

coronaviridae

Bovine Coronavirus Transmission

fecal-oral route (esp calves)

aerosol or resp droplet

higher in crowded or stressful situations

Bovine Coronavirus pathogenesis

virus reps in epithelial cells of SI and LI

Bovine Coronavirus Symptoms

calf diarrhea

winter dysentery: sudden onset of bloody diarrhea, reduced milk prod, milk resp signs

resp disease: nasal discharge, coughing, often part of BRD complex

Bovine Viral Diarrhea Virus (BVDV) virus type

flavivirus

Bovine Viral Diarrhea Virus (BVDV) transmission

horizontal: direct contact with infectious body fluids

vertical: transplacental infection to fetus

Bovine Viral Diarrhea Virus (BVDV) epidemiology

worldwide presence

Bovine Viral Diarrhea Virus (BVDV) Symptoms

subclinical infection: most common, mild or no apparent signs

acute: fever, depression, diarrhea, decreased milk prod

reproductive losses: abortions, congenital defects

immunosuppression: can predispose to secondary infections (resp disease)

hemorrhagic syndrome

Bovine Viral Diarrhea Virus (BVDV) persistent infections

occurs when a fetus is infected in utero with a non-cytopathic strain before its immune system fully develops

these animals continuously shed high levels of virus and serve as a major reservoir in the herd

Bovine Viral Diarrhea Virus (BVDV) mucosal disease

occurs in persistently infected animals when the non-cytopathic strain mutates or a cytopathic strain is superimposed

Bovine Viral Diarrhea Virus (BVDV) mucosal disease symptoms

severe erosions/ulcers in the mouth, esophagus, and throughout GI tract

profuse diarrhea, dehydration

high fever, rapid weight loss, extreme depression

near 100% mortality rate once clinical signs appear

Bovine Respiratory Syncytial Virus (BRSV) Virus Type

paramyxovirdae

Bovine Respiratory Syncytial Virus (BRSV) epidemiology

causes significant resp disease in cattle

global distribution: outbreaks often occur in autumn/winter

high morbidity, typically low to moderate mortality

Bovine Respiratory Syncytial Virus (BRSV) transmission

primarily thorugh aerosol or direct contact w resp secretions

Bovine Respiratory Syncytial Virus (BRSV) symptoms

resp distress: tachypnea, dyspnea, open-mouth breathing

coughing, nasal discharge, ocular discharge

fever, lethargy, reduced feed intake

Bovine Respiratory Syncytial Virus (BRSV) pathogenesis

induces syncytia (fusion of infected cells) leading to inflammation and necrosis

Parainfluenza-3 (PI3) Virus Type

typically mild alone but can exacerbate or predispose to secondary infections

causes upper resp disease

Parainfluenza-3 (PI3) Transmission

Aerosols, direct contact w infected nasal secretions

Parainfluenza-3 (PI3) Symptoms

often subclinical or mild resp disease

nasal discharge, mild cough, elevated resp rate

possible mild fever, reduced appetite

Parainfluenza-3 (PI3) Treatment, Control, and Prevention

vaccines, biosecurity measures

Rinderpest Virus Type

paramyxovirdae

Rinderpest significance

second disease in history to be declared globally eradicated

Rinderpest Epidemiology

endemic in Africa, mid east, asia

high contagiousness; mortality could approach 100% in naive herds

Rinderpest Transmission

direct contact, contaminated water, feed, fomites with secretion/feces

Rinderpest Symptoms

high fever, depression, anorexia

necrotic stomatitis (oral erosions), profuse salivation, nasal discharge

severe diarrhea, often bloody, leading to dehydration and death

rapid course: death can occur within a week of symptom onset

Avian Influenza Virus Type

Orthomyxoviridae

Avian Influenza in cattle timeline

basically first noticed in early 2024 and since march 2024 numerous dairy cattle farms across multiple states have tested positive

Avian Influenza spread to cattle

potential routes: movement of infected animals, contaminated milk, people and equipment

Avian Influenza symptoms in cattle

often subclinical or mild

possible mild resp signs

very rarely fever or decreased feed intake

Avian Influenza Treatment, control, and prevention

biosecurity, surveillance, public health

Foot and Mouth Disease Virus Type

picornaviridae

Foot and Mouth Disease host range

cloven-hooved animals

Foot and Mouth Disease symptoms

highly contagious, rapidly spread

high morbidity, variable mortality

rapid onset: signs typically appear 2-14 after infection

fever: high fever usually first sign

vesicles (hallmark of FMD): mouth, feet, teats

excessive salivation

reduced milk prod

Foot and Mouth Disease facts

foreign animal disease and reportable disease