Miscellaneous Diseases of Cattle

L. O. MOTT AND C. A. MANTHEI.

MUCOSAL diseases are relatively new diseases of cattle in the United States. They affect the mucous membranes or tissues that line the digestive and respiratory systems.

Some of the diseases are caused by viruses (bacteria-free filtrates), but the causes of others have not yet been determined. Bacteria have been eliminated as the causative agent in nearly all instances.

When the disease affects the mucous membranes of the digestive tract, diarrhea is a common symptom; sometimes, therefore, it is called virus diarrhea.

These diseases are important because of the economic losses and because of their clinical resemblance to rinderpest, a serious virus disease that occurs in parts of Asia and Africa but has not appeared in the United States.

There are now recognized in the United States four or more different diseases of cattle that belong to the mucosal disease group: New York virus diarrhea, Indiana virus diarrhea, Iowa mucosal disease, and rhinotracheitis.

They are similar to (and probably should be grouped with) malignant catarrhal fever and bluetongue of cattle, both of which are exotic diseases but probably exist in this country. It is Possible also that some of these diseases may have a part in the syndrome of shipping fever.

The first of the mucosal diseases was recognized and identified as New York virus diarrhea in 1946 by Peter Olafson, A. C. MacCallum, and F. H. Fox, of Cornell University. One or more of the diseases, however, may have been present in the United States before then, according to reports in the American Veterinary Medical Association Journal for March 1920.

New York virus diarrhea of cattle was the first mucosal disease in the United States identified (in 1946) as to virus origin and later differentiated from rinderpest by R. V. L. Walker, of the Dominion Department of Agriculture of Quebec, and Dr. Olafson. It is an infectious, febrile, transmissible disease, characterized by profuse diarrhea, ulcers, and erosions of the digestive tract.

An incubation period of 7 to 9 days usually is followed by a sudden rise in temperature, lack of appetite, depression, a drop in the number of white blood cells, diarrhea, coughing, ulcers, and erosions of mucous membranes. Pregnant cows may abort 10 to 90 days after the onset of the acute stage.

Young animals seem to react more severely and may be more susceptible than older ones. Animals that have recovered are immune to reinfection.

Incidence of the disease in early outbreaks was 33 to 88 percent. The variation might have been due to the strain of virus and individual resistance or partial immunity from previous exposure to the virus. The death rate in early outbreaks in New York averaged 4 to 8 percent of the affected animals. In later years the morbidity was less than 5 percent and the mortality was about 50 percent of the sick animals.

The geographic distribution and extent of the disease are probably greater than is generally supposed, because many animals from almost all sections of New York, exposed with challenge virus, were resistant to infection. Virus has been isolated from animals in New York, Connecticut, Maine, and California. Shortly after the disease appeared in New York, a similar disease was reported in Canada and in Sweden in 1951. Immunological comparisons of the virus strains in the United States indicate they are of the same immunological type. No comparisons have been made between the New York virus and the Canadian and Swedish viruses.

Serological identification tests, including complement-fixation and serum-neutralization tests, have been unsuccessful. A limited number of experimental inoculations were made into fertile chicken eggs, guinea pigs, swine, dogs, cats, goats, sheep, mice, and rabbits. They were successful only in rabbits.

When a virus can be inoculated into and live in an artificial host (the rabbit in this instance) and then is forced to live in this environment for many generations, it frequently loses its ability to produce sickness of the natural host (in this case, the cow). Such a changed virus, even though it no longer can produce disease, frequently has the ability to produce an immunity against the virulent disease in the natural host and may be of value for a live-virus vaccine. Because this virus that was transferred through 75 passages in rabbits became modified in virulence for cattle, it could be considered for vaccine immunization.

INDIANA VIRUS DIARRHEA, a mucosal disease of cattle similar in clinical appearance to New York virus diarrhea, appeared in Indiana in 1954.

The natural disease has been observed only in steers. The disease was transmitted experimentally to calves of both sexes with bacteria-free virus filtrates prepared from the blood of diseased animals. The incubation periods were 1 to 3 weeks. A sudden rise in temperature, loss of appetite, depression, increased heart action, and rapid respiration followed. Those symptoms were followed by nasal discharges, coughing, lameness, and diarrhea, accompanied with muzzle, mouth, and intestinal lesions characterized by circular areas of inflammation, and erosions of the mucous membranes. Similar lesions were observed in the openings in the nose and in the vulva and vagina of inoculated cattle.

The incidence of disease in affected herds was almost 100 percent. The mortality rate was 4 to 20 percent. The disease ran its course in 2 to 4 weeks in most instances.

This virus disease seems clinically, hematologically, and pathologically almost indistinguishable from New York mucosal disease virus diarrhea, but immunologically it appears to be a different disease. Animals that recovered from the Indiana virus disease were immune to challenge with the Indiana virus but were susceptible to exposure with the New York virus, whereas recovered animals from the New York virus were susceptible to challenge with the Indiana virus.

Iowa mucosal disease of cattle was first observed by F. K. Ramsey and W. H. Chivers in a 10-month-old, Hereford steer admitted to the veterinary clinic at Iowa State College in 1951. By 1953 the disease had appeared on about 100 Iowa farms and on several farms of the adjoining States.

Reports from a national survey in 1955 indicated the disease had spread to all the States around Iowa and to other States. Eighteen States and one Territory reported presence of the disease.

The Iowa mucosal disease presents a clinical and pathological picture like the New York virus diarrhea and Indiana virus diarrhea, but it differs from them in that the number of sick animals in a herd is usually low, probably averaging 2 to 5 percent. The mortality rate in clinical cases is practically 100 percent.

Experimental transmissions of the disease were unsuccessful until 1955, when scientists at Purdue University reported transmission with bacteria-free disease tissue suspension filtrates. The cause of the disease appears to be a virus. No satisfactory treatment has been developed.

The body temperature rises for 24 to 48 hours during the early stages of the disease. Later it returns to normal. Other symptoms are complete loss of appetite, watery diarrhea (sometimes mixed with blood), drooling of saliva,depression, rapid loss of weight, and ulcers of the mucous membranes of the nostrils, muzzle, lips, gums, tongue, and mouth cavity. Some animals have a watery discharge from the eyes, opacity of the cornea, and lameness.

Nearly all the affected animals die within 3 to 10 days.

It is likely that many animals in affected herds have developed an inapparent or nonclinical form of the disease because there have been no records of recurrence of the disease on the same farm an indication that a herd immunity developed. Some attempts at transmission from sick animals to normal calves resulted in incubation periods of 2 to 8 days after inoculation. Temperature reactions lasting 2 to 5 days followed, but no other evidence of a clinical disease developed.

All of the common beef and dairy breeds have been involved. Most of the animals have been 6 to 14 months old. No seasonal factor has been associated with the occurrence of the disease, but in Iowa most of the cases occurred in winter and early spring.

That affected herds may be 20 miles or more apart suggests that insects transmit the disease, although it is true that we usually associate insect vectors with seasonal diseases. There is no evidence that the Iowa mucosal disease is transmitted by contact.

RHINOTRACHEITIS (red nose, California influenza-like disease) is a contagious, acute virus disease of cattle. It involves mainly the mucous membrane of the upper respiratory tract. It occurred in the dairy cattle of Los Angeles County and surrounding counties of California from October 1953 to February 1954. An outbreak, which lasted 6 weeks, occurred in dairy herds in the Stockton area as the disease was subsiding in the Los Angeles area. The following year the disease appeared again in feeder cattle near Stockton. Almost simultaneously it appeared in feeder herds in the Imperial Valley and recurred in dairy cattle in the Los Angeles area. The outbreaks lasted 2 to 3 months.

About 10,000 animals were in those herds. About 22 percent of them became infected. The mortality rate was 2 to 3 percent.

An outbreak of a disease condition similar to the California influenza-like disease was reported in Colorado in January and February of 1955. It involved 250,000 feeder cattle in the northeast quarter of Colorado. An average of 50 percent of the animals in affected herds became sick. Mortality was about 1 percent. The disease was previously observed in Colorado as early as 1950 and continued occurring annually in a few scattered herds of feeder cattle until 1955, when the big outbreak developed.

The disease first caused an abrupt cessation of milk flow and high temperatures, with little evidence of other symptoms, among dairy cattle in California. Temperatures continued high for 3 or 4 days before returning to normal. During the second and third days of sickness there was some drooling of saliva, slight nasal discharges, slight depression, increased respiration, and occasional coughing. Some animals had impaired appetites. There was no change in white-blood-cell counts.

Most of the cows returned to the milking string after 7 to 10 days. Dairy calves had similar symptoms without any evidence of depression. They also had a conjunctivitis, with a marked discharge of tears.

The disease usually appeared in beef or feeder cattle 3 to 6 weeks after the animals had been placed on feed. High temperatures, which usually returned to normal after a few days, attended the initial stages. Temperature reactions are associated with depression, increased respirations, a marked inflammation of the upper respiratory tract (including the nose openings, pharynx, larynx, and trachea) with various degrees of mucous discharges, drooling of saliva, and eye trouble.