Viral causes of infertilty in male (Cattle, buffalo and others) by Sabal Pokharel.

1. VIRAL CAUSES OF INFERTILITY IN
MALE
Prepared by
Sabal Pokharel
9th sem, BVSC&AH, HICAST

2. INTRODUCTION
• Different viral agents have been isolated from bovine semen. Some may be freely
found in seminal plasma and others become firmly adhered to the sperm head
and thus may not just infect cows through seminal plasma but also lead to the
possibility of direct infection of oocytes.
• The difficulty regarding viral agents reported in bovine semen lies in the fact that
a good number of such agents produce chronic or persistent infection.
• Several studies have been carried in an attempt to eliminate viruses from semen,
but with poor results.
• Some studies have reported certain effectiveness with washing semen through
procedures such as Percoll or Swim-up which lead to producing embryos in vitro,
even though there are no conclusive studies on the matter.

3. Viral Disease Transmitted Through Semen
Infectious Bovine
Rhinotracheitis
Bovine Viral Diarrohea
Foot and Mouth Disease
Vesicular stomatitis
Blue tongue
Contagious Bovine
Pleuropneumonia
Sheep and Goat pox
Lumpy skin disease
Classical swine fever
African swine fever
Rinderpest
PPR

4. Infectious Bovine Rhinotracheitis
Etiology
• This is a respiratory disease which is produced by bovine herpesvirus, type1
(BHV1), belonging to the Herpesviridae family.
• dsDNA, Enveloped
• According to genomic and antigenic analysis, BHV-1 is divided into BHV-1.1 and
BHV-1.2, in turn being subdivided into subtype BVH-1.2 and BHV-1.2b.
• When BHV-1 affects the genital tract of cattle it causes Infectious pustular
vulvovaginitis/ Infectious pustular balanopostitis.
• BHV-1 may also cause conjunctivitis, reproductive disorders and neonatal mortality.

5. INFECTIOUS BOVINE RHINOTRACHEITIS
Transmission
Direct transmission occurs through contact with
• Acutely infected animals
• Latently infected animals in which reactivation of the virus takes place
Indirect transmission may occur through
• Contaminated semen
• Embryo transfer
• Humans
• Contaminated materials
• Airborne transmission

6. INFECTIOUS BOVINE RHINOTRACHEITIS
• This is one of the most important viral diseases as the state of viral latency
implies that infected animals become carries for life and frequent viral
reactivation is caused by stress factors.

7. INFECTIOUS BOVINE RHINOTRACHEITIS
Clinical Features
Infectious Pustular Balanoposthitis (IPB)
• The prepuce may be swollen and a
mucopurulent discharge may be seen.
• Often lesions are only obvious on
extrusion of the penis.
• Some bulls lose their libido and find
erection and ejaculation painful.
Animal often shows symptoms like
following
• Fever (as high as 42°C)
• Depression
• Loss of appetite
• Reddening of the mucous membranes
• Ulceration / reddening of the upper
airway

8. INFECTIOUS BOVINE RHINOTRACHEITIS
Reproductive effects
• Bulls affected during an outbreak of the disease showed signs like pyrexia, uni or
bilateral orchitis and azoospermia.
• Mononuclear infiltration of the connective tissue, without neutrophils and
degeneration of the germinal epithelium was found in one of the testicles
examined by histopathology.
• IBR-infected bulls eliminate the virus in semen during their whole lives, even
though it has been thought that the virus cannot be eliminated from seropositive
bulls if they are managed with low levels of stress.
• The presence of the virus was detected in the post-nuclear region of the sperm,
cephalic hood in a bull from a farm having fertility problems.

9. INFECTIOUS BOVINE RHINOTRACHEITIS
• The worldwide literature is abundant regarding recognising this virus
transmission through semen or embryos.
• Sanitary legislation thus establishes sever restrictions on importing biological
material from countries where the disease is prevalent
• More recently, the World Organization for Animal Health (OIE) has included
sanitary policy regarding this virus (as well as other pathogens) in its guidelines
concerning the taking of bovine semen, its treatment and recollecting and
manipulating cattle embryos.
• A new type of virus, bovine herpes virus type 5 (BHV-5), having 85% genetic
homology with BHV-1, is responsible for neurological problems in calves, having a
high rate of lethality; it has been isolated from semen.

10. INFECTIOUS BOVINE RHINOTRACHEITIS
Diagnosis
• Clinical signs of IBR are indication of BVH-1 infection but still require laboratory
test for confirmation.
• Post mortem of affected animal shows congestion of tracheal lining with
hemorrhage.
• PCR or Fluorescent antibody testing or ELISA for detection of active infection
• Virus neutralization test
Retrospective diagnosis of BHV-1 infection can be made by measuring antibody
levels in paired sera samples. First sample is collected during the clinical phase
and a second sample is collected 4 weeks later

11. INFECTIOUS BOVINE RHINOTRACHEITIS
Prevention and Control
• Selective culling and Isolate carrier cattle from herd
• Biosecurity with strict isolation and quarantine.
• Quarantine animal for 21 days separating from herd.
• Vaccination
• Castrate IBR positive bulls.
• Monitoring with appropriate screening programs
• Avoid mating of animal with stray bulls

12. BOVINE VIRAL DIARROHEA
Etiology
BVD is caused by Pestivirus of Flaviviridae.
Enveloped, +ve ssRNA
Initially it was recognized in 1940’s.
Currently BVDV has 2 strains i.e. BVD-1 and BVD-2.
BVD1 is very diversed in different subgroups but regardless to their diversity all
BVD are either of cytopathic or non cytopathic biotypes.

13. BOVINE VIRAL DIARROHEA
Transmission
The main mode of transmission is through the oral route, but the disease may also
be transmitted by inhalation and artificial insemination using semen of persistently
infected bulls.
Pathogenesis
Lymphoid tissue is the primary replication site of virus which leads to
immunosuppression and enhanced severity of intercurrent infection.
The virus replicate also itself in Prostate, seminal vesicles, epididymis.
The antigen has also been detected in epithelial cells of epididymis, urethra, sertoli
cells, accessory glands and spermatogonia cells.

14. BOVINE VIRAL DIARROHEA
Clinical features
• Most transient symptoms includes low grade fever as well as high fever (upto
107°F), diarrohea, dehydration, oral ulceration, eruptive lesion on coronary band
and coughing. Rarely animal suffering from acute infection shows high grade
fever and bleeding from internal organs.
• A marked effect on spermatic quality has been observed in experimentally
infected bulls, consisting of low concentration, low motility and an increase in the
frequency of primary spermatic abnormalities.
• Following initial infection, the virus stays in the testes for up to 7 months.
• Another study has presented the elimination of the virus from semen during an
11-month period in the presence of active antibodies but it has been regarded as
an exceptional case.

15. BOVINE VIRAL DIARROHEA
• The BVD virus may be present in the semen of animals suffering acute infection
or in persistently infected animals.
• Persistently-infected animals (even though very few become breeding animals)
are those representing the highest risk regarding BVD transmission through
semen since viral elimination from semen is much higher than from acute
infections.

16. BOVINE VIRAL DIARROHEA
Diagnosis
• Numerous methods has been developed to diagnose both persistant and acute
infection.
• These includes antigen capture (AC), ELISA, Immunohistochemistry, RT-PCR, Virus
isolation etc.
• Serological examination
• RT- PCR test for active infection.
• Blood drawn from acute phase can be proceed for virus inoculation from WBC
(buffy coat)
• If serum sample one from acute case and other from few weeks later are taken
then rise in serum antibody between both samples confirms BVD infection.

17. BOVINE VIRAL DIARROHEA
Contd..
• Necropsy findings and serological test confirms BVD by revealing ‘Disease of
Mucosa’ in infected animals.
• Persistantly infected animals are easy to detect as they shed too many virus that
viral antigen in serum confirm BVD infection.
• Other method for detection are Skin notch testing, Whole Blood viral antigen etc.

18. BOVINE VIRAL DIARROHEA
Prevention and Control
• Vaccination: Modified live vaccine are most effective but inactivated and
combined vaccines can also be used.
• Biosecurity. To lower the PI animals.
• Testing for persistant infection in male.
• Best management practice in farm.
• Disinfect premises and destroy feeds and fodders.
• Destroy frozen semen from the past month prior to outbreak.

19. FOOT AND MOUTH DISEASE
Etiology
• Apthovirus of Picornavirus family.
• ssRNA (+ve sense), Non-enveloped, Isoherdral capsid made up of 60 capsomeres.
Strains
 7 strains i.e. O, A, C, SAT-1, SAT-2, SAT-3, ASIA 1
 Type O strain is most prevalent in Nepal.

20. FOOT AND MOUTH DISEASE
Transmission
Most common route is Aerosol.
Secretion and Excretion: milk, semen, feces, urine, vaginal discharge, nasal
discharge, saliva, ruptured vesicles etc.
Animal products and Equipements.
Foot and mouth disease virus could be transmitted in bull semen before the
infected bull shows any signs of disease.
The disease has been shown to be transmissible when susceptible females were
inseminated with semen from virus shedding bulls. It is found that FMD virus can
survive in semen in freezing procedures in liquid nitrogen.

21. FOOT AND MOUTH DISEASE
Pathogenesis
• After entry of virus it has incubation period of 9-12 days. Virus first replicates in
pharyngeal tissue (Primary viral replication) then causes viraemia in 24-72 hours.
Then further replication of virus occurs in multiple epithelial cells lymph nodes,
mammary glands and other organs where there is formation of vesicles within
group of epithelial cells.
• Foot and mouth disease causes severe degeneration of germinal epithelium of
the testes of bulls. The semen picture was severely adversely affected
• The virus carrier stage has been shown to persist in some cattle for many months
following recovery from the disease or following prophylactic immunization

22. FOOT AND MOUTH DISEASE
Clinical features
High fever, Anorexia, stomatitis, Increased Salivation.
Infertility in bulls and Abortion in females.
Vesicles at feet, tongue, coronary bands, buccal mucosa, teats etc.
FMD impairs fertility and livestock productivity by both increasing the age of first
calving and increasing the time to conception.
Lesions includes Vesicles formation different body parts, tiger heart lesion in L.V.
wall of heart, Myocarditis, hyaline degeneration and necrosis of muscle fibre,
ballooning degeneration of cells in middle of stratum spinosum of epithelium.

23. FOOT AND MOUTH DISEASE
Diagnosis
Virus inoculation in BHK cell and culture.
Inoculation done in footpad or tongue of guinea pig shows vesicles on tongue
and paralysis and death occurs.
CFT
Immunofluorescence tests
Identification by Multiplex PCR
ELISA

24. FOOT AND MOUTH DISEASE
Prevention and Control of FMD
• Strict biosecurity measures for
animal, its products, vehicle,
equipements etc.
• Restriction of animal movement with
effective quarantine (>14 days)
• Mass vaccination
• Culling of affected animals
• Migration control and monitoring
• Formite and vector control
• Cleaning and disinfection of farm
• Clinical surveillance
• Control of cross border livestock trade
• Avoid frozen sperm from area of
outbreak

25. Vesicular Stomatitis
Etiology
• Vesiculovirus of Rhabdoviridae
• ssRNA(-ve)
• There are two distinct classes of VSV recognized i.e. New Jersey (NJ) and Indiana
(IND)

26. Vesicular Stomatitis
Transmission
• The virus can be transmitted through direct contact with infected animals with
clinical disease or by biting insects.
• Black flies (Simulidae), sand flies(Lutzomyia), and biting midges (Culicoides
spp) have been shown to be competent vectors, but other insects may act as
mechanical vectors as well.
• The prevalence of clinical cases in a herd is generally low (10%–20%), but
seroprevalence within the herd may approach 100%.
• Morbidity rate is variable upto 90%.
• Low mortality.

27. Vesicular Stomatitis
Pathogenesis
• Local infection of the mucous membrane of the mouth and the skin around the
mouth and coronets is followed by the development of vesicles on the lips,
muzzle, tongue, and also on the teats and interdigital clefts.
• The frequent absence of classical vesicles on oral mucosa of affected animal in
field outbreaks has led to careful examination of the pathogenesis of the mucosal
lesions.
• Even in experimentally produced cases, only 30% of lesions develop as vesicles,
the remainder dehydrate development and terminate by eroding as a dry
necrotic lesion.

28. Vesicular Stomatitis
Clinical features
• The incubation period for vesicular stomatitis is 2–8 days and is typically followed
by a fever.
• Ptyalism is often the first sign of disease. Vesicles in the oral cavity are rarely seen
in naturally occurring cases because of rupture soon after formation.
• Infertility in viraemic bulls.
• Ulcers are the most common lesion seen during initial examination. Ulcers and
erosions of the oral mucosa, sloughing of the epithelium of the tongue, and
lesions at the mucocutaneous junctions of the lips are commonly seen.
• The disease is generally self-limiting and resolves completely within 10–14 days.
• Virus-neutralizing antibodies to either serotype persist and have been
documented in individual horses that had previous clinical disease for 10–12
years after an outbreak, but reinfection can occur after a second exposure.

29. Vesicular Stomatitis
Prevention and control
• Sanitation
• Insect control program
• Segregation and Isolation of affected animals.
• Avoid grazing in bushy areas.

30. THE END