Foot-and-Mouth Disease Virus-Associated Abortion and Vertical Transmission following Acute Infection in Cattle under Natural Conditions

Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals, including domestic and wild host species. During recent FMD outbreaks in India, spontaneous abortions were reported amongst FMD-affected and asymptomatic cows. The current study was an opportunistic investigation of these naturally occurring bovine abortions to assess causality of abortion and vertical transmission of FMDV from infected cows to fetuses. For this purpose, fetal tissue samples of eight abortuses (heart, liver, kidney, spleen, palatine tonsil, umbilical cord, soft palate, tongue, lungs, and submandibular lymph node) were collected and screened by various detection methods, including viral genome detection, virus isolation, and immunomicroscopy. Amongst these cases, gross pathological changes were observed in 3 abortuses. Gross pathological findings included blood-tinged peritoneal and pleural effusions and myocarditis. Hearts of infected calves had mild to moderate degeneration and necrosis of the myocardium with moderate infiltration by mixed inflammatory cells. Localization of FMDV antigen was demonstrated in lungs and soft palate by immunomicroscopy. FMDV serotype O viral genome was recovered from 7 of 8 cases. Infectious FMDV serotype O was rescued by chemical transfection of the total RNA extracted from three soft palate samples and was sequenced to confirm 100% identity of the VP1 (capsid) coding region with isolates collected from infected cattle during the acute phase of infection. Based upon these findings, it may be concluded that FMDV-associated abortion occurred among the infected pregnant cows included within this study and FMDV was subsequently transmitted vertically to fetuses. This is the first documentation of FMDV-associated abortions in cattle.

Myocarditis Associated with Foot-and-Mouth Disease Virus Type O in Lambs

The present study describes the pathogenetic mechanisms of myocarditis in 9 lambs that died in a foot-and-mouth disease outbreak in Samsun, Turkey. In all the heart samples tested, ELISA and sequencing for phylogenetic analyses showed that the virus, namely O/TUR/Samsun/05, was associated with the PanAsia pandemic strain of foot-and-mouth disease virus (FMDV) type O. The lambs had myocardial lesions but no typical vesicular lesions. In situ reverse transcription showed that many cardiomyocytes and some interstitial cells were positive for FMDV type O. Inflammatory infiltration, hyaline degeneration, and necrosis of sheets of myocytes were observed. The cellular infiltrates were mononuclear cells, including many lymphocytes, macrophages, a few plasma cells, and neutrophils. Major histocompatibility complex Class II+ dendritic and mononuclear cells, γδ T cells, CD172A+ and CD14+ macrophages and monocytes, and IgM+ B cells were detected mainly in the infected hearts. Inducible nitric oxide synthetase (iNOS) was seen mostly in areas of inflammation infiltrated by large numbers of cells. Of the 2 α-subunits of integrin known to be used as receptors by FMDV in epithelial tissues, CD49e (integrin α5) was detected in the membranes of cardiac myocytes with intercalated discs, but CD51 (integrin αV) was not detected in cardiac myocytes from infected or normal lambs. Interstitial and inflammatory cells were positive for both integrin subunits. The terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL)-positive signal was detected in the nuclei of both cardiac myocytes and interstitial cells from infected lambs. These findings suggest that the iNOS expressed by inflammatory cells in lesions may have a deleterious effect on cardiac myocytes in these lesions.

Dioxins and polychlorinated biphenyls (PCDD/Fs and PCBs) in food from farms close to foot and mouth disease animal pyres

To control the outbreak of foot and mouth disease, which occurred in the UK in early 2001, a large number of farm animals were slaughtered. Where it was not possible to render or landfill the carcasses, they were destroyed by burning on open pyres, with wood, coal and other materials. Uncontrolled combustion such as this is known to produce small quantities of dioxins and an investigation was made into whether, as a result of the burning, there was an elevation in the concentrations of these compounds in food produced in the areas close to the pyres. With few exceptions, concentrations of PCDD/Fs and PCBs were within the expected ranges as predicted by reference data. No accumulation over time was evident from a repeat milk sampling exercise. Where elevated concentrations of PCDD/Fs and PCBs were found in chickens and eggs, they were in samples not destined for the food chain. Elevated levels in some samples of milk from Dumfries and Galloway were not found in earlier or later samples and may have been found as a result of a temporary feeding regime. Elevated concentrations in lamb from Carmarthenshire were from very young animals which would not have entered the food chain. There was no evidence of any significant increase in dietary exposure to PCDD/Fs and PCBs as a result of the FMD pyres.

Surgical treatment of a sloughed hoof by skin grafting in a young bull

A sloughed hoof in a young bull as a sequela of foot and mouth disease was treated by skin grafting. Skin blocks obtained from the craniolateral thoracic area of the same animal were placed in slit-like pockets created on the coronary band. New hoof formation was completed within 20 weeks.

Human repercussions of foot and mouth disease and other similar viral diseases

Foot and mouth disease is a frequent viral zoonosis in livestock that may occasionally also affect humans. Transmission to man usually occurs as a result of the consumption of unprocessed milk. The clinical manifestations include fever, headache, weakness, muscle pain, and the development of vesicles and ulcers throughout the oral mucosa. Vesicular stomatitis is another zoonosis similar to foot and mouth disease that can likewise affect humans with similar clinical manifestations, in which the presence of aphthae is highly suggestive. In turn, hand, foot and mouth disease and herpangina are two exclusively human diseases caused by different enteroviruses, with a special predilection for children under five years of age, and characterized by the presence of vesicles and ulcerations in the oral cavity. The present study provides a brief review of the salient characteristics of foot and mouth disease and of other similar viral diseases with which the differential diagnosis should be established.

Viral infections and bovine mastitis: a review

This review deals with the role of viruses in the aetiology of bovine mastitis. Bovine herpesvirus 1, bovine herpesvirus 4, foot-and-mouth disease virus, and parainfluenza 3 virus have been isolated from milk from cows with clinical mastitis. Intramammary inoculations of bovine herpesvirus 1 or parainfluenza 3 virus-induced clinical mastitis, while an intramammary inoculation of foot-and-mouth disease virus resulted in necrosis of the mammary gland. Subclinical mastitis has been induced after a simultaneous intramammary and intranasal inoculation of lactating cows with bovine herpesvirus 4. Bovine leukaemia virus has been detected in mammary tissue of cows with subclinical mastitis, but whether this virus was able to induce bovine mastitis has not been reported. Bovine herpesvirus 2, vaccinia, cowpox, pseudocowpox, vesicular stomatitis, foot-and-mouth disease viruses, and bovine papillomaviruses can play an indirect role in the aetiology of bovine mastitis. These viruses can induce teat lesions, for instance in the ductus papillaris, which result in a reduction of the natural defence mechanisms of the udder and indirectly in bovine mastitis due to bacterial pathogens. Bovine herpesvirus 1, bovine viral diarrhoea virus, bovine immunodeficiency virus, and bovine leukaemia virus infections may play an indirect role in bovine mastitis, due to their immunosuppressive properties. But, more research is warranted to underline their indirect role in bovine mastitis. We conclude that viral infections can play a direct or indirect role in the aetiology of bovine mastitis; therefore, their importance in the aetiology of bovine mastitis and their economical impact needs further attention.

[Clinical picture and differential diagnosis of foot and mouth disease in cattle]

Foot-and-mouth disease (FMD) in cattle is characterized by the formation of vesicles and erosions in the mouth, teats and feet. Despite extremely high morbidity, mortality in adults is usually very low, however up to 50% of calves dies due to cardiac involvement or secondary infections. This paper describes the signs of FMD in cattle as well as those of other diseases which causes similar lesions in this species.

African swine fever interference with foot-and-mouth disease infection and seroconversion in pigs

Initial oral infection of pigs with either highly virulent (L-60) or moderately virulent (DR-2) African swine fever virus (ASFV), followed in 3 days with exposure to foot-and-mouth disease virus (FMDV) (tongue inoculation and contact), failed to cause FMDV infection or seroconversion in 18 of 22 L-60-infected pigs and 13 of 34 DR-2-infected pigs. Of the 13 DR-2-infected pigs remaining free of foot-and-mouth disease (FMD), 2 pigs survived to 24 days without antibody to FMDV, despite constant contact with clinically infected pigs with FMD. Three other DR-2-infected pigs never developed FMD lesions but did develop low levels of antibody to FMDV by day 17. A group of larger pig (in which DR-2 is less virulent) infected with DR-2 and then FMDV had a rapid but suppressed immune response to FMDV. Contact pigs introduced 3 days postinoculation and inoculated with FMDV only all became infected with ASFV by contact and died. This remarkably long lasting 1-way interference with FMD infection during acute and subacute African swine fever was not anticipated. Infection with ASFV may have blocked the initial target cells (possibly dendritic cells) necessary for establishment of FMDV infection.

Protective and immunostimulating activity of a low dose of cyclophosphamide in the experimental infection of mice with foot-and-mouth disease virus

Administration to mice of a low, non-immunosuppressive dose of cyclophosphamide 4 days before infection with foot-and-mouth disease virus decreases viral replication, enhances the immune response against the virus and prevents pancreatic damage.

Alterations of exocrine pancreatic enzymes in virus-induced diabetic cattle as revealed by immunohistochemistry

The pancreatic tissue of normal and virus-induced diabetic cattle was investigated by the indirect immunofluorescence technique. Seven secretory proteins (chymotrypsinogen A, trypsinogen, carboxypeptidase A, RNase, DNase, alpha-amylase and lipase) were localized in normal bovine pancreatic acinar cells but in diabetic animals amylase, lipase and carboxypeptidase were either not detectable or markedly diminished. Decrease in amylase content has been reported previously in other diabetic animals. The diminution of the three pancreatic enzymes may be related to the destruction of pancreatic endocrine tissue that occurs in these diabetic animals.

[Isolation of foot-and mouth disease virus in swine with other diseases]

The authors took a survey of foot-and-mouth disease samples of myocardium and tonsil from swine which was died without clinicals signs of foot-and-mouth disease, with isolation of virus, type O, A and C. It was observed and accentuated relation between the incidence of hog cholera, pneumonia and atipic foot-and-mouth disease, especially from suckling pigs.