Epidemiological and diagnostic studies on Bovine Viral Diarrhea-Mucosal Disease

complex (BVD-MD) in cattle

M. Sayed-Ahmed1 , S. Atwa1, E. E. Younis 1, S. A. Zeidan2

1Department of Internal Medicine, Infectious Diseases and Fish Diseases, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt

2Rinderpestlike Diseases Department, Veterinary Serum and Vaccine Research Institute, Abbasia, Cairo

BDV/MD complex•One of the production limiting diseases in dairy herd (Radostits et al., 2007).

Intr

od

ucti

on • Acute transmissible disease caused by RNA virus, genus Pestivirus

within the family Flaviviridae and is closely related to border disease virus (BDV) of sheep and classical swine fever virus (CSFV) (Heinz et al., 2000)

• Calves of 4 weeks to 4 months age appeared to be the most

commonly affected with BVD-MD complex (Evermann and Faris, 1981).

• 80% of BVD-MD cases were recorded in cattle less than 1 year old with morbidity rate ranged from 3-14% and mortality rate 90% independent on age of animal (Doll, 1986).

• Because of the high economic losses of this virus, awareness of BVD eradication has increased substantially during the past decade (Moennig

et al., 2005).

BDV/MD complexThe implementation of a programme to control the infection must be based on:

Intr

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• secondly, the clearance of virus shedders from the infected herds and thirdly, control measures to prevent the transmission of the virus within and between herds (Bitsch and Ronsholt, 1995).

• First, the identification of animals and herds both free from infection or presence of active infection.

Aim of study was directed to:

Intr

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ucti

on

• Seroepidemiological survey on serum samples randomly collected from infected herds

• Isolation and identification of BVDV from clinically suspected cattle.

Study animals M

ate

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A total of 2342 crossbreed cattle were clinically observed from May2008 to April 2009 for BVD clinically suspected cattle

Age < 2 month

2-4 month

5-8 month

9-12 month > 1 year Total

Dakahlia 150

81

173

123

695

1222

Damietta

70 220

150 80

600

1120

Total

220

301

323

203

1295

2342

Classification of animals according to their localities and ages

Viral isolation

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It was carried out according to the method described by Zeidan (1986)

The indirect fluorescent antibody technique was performed for identification of isolated viruses according to Kviensdal et al. (1989).

Immunofluorescence

Tissue specimens collected from dead calves were fixed in 10% formalin and stained by Hematoxylin and Eosin (H&E) after (Harris, 1998).

Histopathology

Serum Neutralization Test (SNT)

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Test was performed according to Cerberey and lee (1966).

1. Clinical findingsR

esu

lts

Governorates Total number of

examined animals

Number of clinically

diseased animals%

Dakahlia 1222 68 5.56

Damietta 1120 56 5

Total 2342 124 5.29

The percentage of clinically BVD suspected infected cattle regarding to the localityof the animals

Clinical signs Suspected cases n =124

%

Respiratory manifestation 46 37.1

Enteric problems 26 20.1

Congenital anomalies 2 1.6

The percentage of suspected diseased animals referring to the different clinical finding of BVD

2. Epidemiological pattern

a. Animal age

Resu

lts

The percentages of clinically BVD suspected infected cattle regarding to the age of the animals

Age Examined animals

(n = 2342)

Diseased animals

(n = 124)

%

< 2 months 220 20 9.09

2 – 4 months 301 27 8.97

9 – 12 months 203 7 3.45

> 1 year 1295 23 1.78

2. Epidemiological pattern

a. Animal age

Resu

lts

The clinical findings observed during examination of clinically diseased cattle

A B

C

A. Calf showing diarrhea (20 days old) B. Calf showing nasal discharges (8month old) C. Calf showing ataxia (1 week old) D. Calf showing disoclusion of jaws

D

2. Epidemiological pattern

b. Season

Resu

lts

The percentages of clinically BVD suspected infected cattle regarding season

Season Examined

animals

(n = 2342)

Suspected

cases

(n =124)

%

Spring

Summer

Winter

Autumn

2342 8 0.34

2342 65 2.78

2342 23 0.98

2342 28 1.19

2. Epidemiological pattern

b. Season

Resu

lts

The percentage of positive BVDV isolated from clinically affected cattle regarding to the season

Season Number of samples

(n = 44)

Positive* (n = 36)

% 

Spring 4 2 50

Summer 32 30 93.75

Winter 2 1 50

Autumn 6 3 50

* There was a significant variation at P < 0.0001

2. Epidemiological patternR

esu

lts

*Infertility troubles: smooth inactive ovary

Clinical signs Number of samples (n =

44)

Positive %* (n =

36)

Respiratory manifestation 23 82.6

Enteric problems 8 62.5

Mixed respiratory & enteric

problems

11 90.9

*Infertility troubles 1 100

Congenital anomalies 1 100

The percentage of positive BVDV isolated from clinically affected cattle regarding to the clinical signs

• Virus isolation and identification

3. Vius isolation R

esu

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The percentages of BVDV positive cells using immunofluroscence

A B

Legend: There was a negative BVDV cells as showed in (A). While n there was a positive cells showed in (B).

4. HistopathologyR

esu

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A. The lung showed thickening in interalveolar septa with collapsed alveoli

B. round cells infiltration was seen in the interstitial tissue besides congested interalveolar capillaries

C. Marked round cells infiltration among cardiac muscle bundles besides congested capillaries

D. The renal tubular epithelial was necrotic besides congestion in the interstitial capillaries

Su

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& C

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• BVD virus is one of the most important pathogen causing economic losses in cattle.

• The age and seasonal variations were important risk factors in the prevalence of BVD infection.

We concluded that:

Thank you for your attention!!!