Infectious diseases of cattle The infectious diseases of adult cattle in New Zealand are reviewed. Diseases of calves and growing stock were in New Zealand reviewed in Surveillance no 2, June 2000. The two Part 2 – adult animals categories of animals could not be partitioned completely, so there is some Causes of overlap with the first article, but additional Only a small proportion of in New Zealand dairy cattle are information pertinent to adult cattle is investigated because most are sporadic. The diagnostic success rate provided here. for abortions submitted to New Zealand veterinary laboratories has Jos Vermunt been about 50% (RN Thornton, pers. comm.). This figure would improve if a full range of tests were to be done routinely, including infection is a well-known cause of placentitis and abortion in cattle, histopathology on placenta, foetal lung, liver, kidney, heart and presumably as a result of eating mouldy hay(7). The common brain; bacteriology on placenta, urine and foetal stomach contents; environmental Mucor/Absidia fungi are sporadic causes of abortion virology on foetal spleen; serology on maternal and foetal blood. in cattle. However, a narrow range of tests is often requested by submitters for Leptospira pomona abortions: Abortions due to L pomona have economic reasons. Non-infectious abortions, such as those caused by declined markedly since vaccination of dairy herds in New Zealand Macrocarpa, Leyland cypress and pine needle ingestion do not became widespread. However, outbreaks of abortion associated with usually cause distinctive lesions, and these comprise a group of L pomona infection can still occur on individual farms, particularly undiagnosed abortions of unknown prevalence. New Zealand has when cows have contact with pigs or their effluent. Aborting cows been free of Brucella abortus infection since 1989(1). are systemically ill, have retained foetal membranes and often Neospora abortions: The protozoan parasite Neospora caninum has develop endometritis. Infected cattle can remain leptospiruric for a world-wide distribution and is a major cause of abortion in New up to 3 months after infection with L pomona(8). Zealand(2). The parasite can be maintained in cattle as a chronic, Ureaplasma abortions: The organism Ureaplasma diversum is a apparently lifelong, infection which can be passed on to the foetus common commensal in cattle both overseas and in New Zealand. during . In some cows, this foetal infection results in an Nevertheless, Ureaplasma infection can cause serious reproductive abortion. However, in many cases, infected cows give birth to a disease and infertility. Pathogenicity depends on the strain of healthy but congenitally infected calf. A congenitally infected heifer organism and host resistance. Clinical disease in cows is calf is capable of transmitting the parasite to the next generation characterised by a granular, lymphoid vulvitis and vaginitis with when she becomes pregnant, thus maintaining infection within small white/grey nodules on the mucosa. The upper reproductive the herd. tract is rarely colonised. In pregnant cows, ascending infections may Neospora abortions can occur throughout gestation but the majority cause sporadic abortions with distinctive placental and foetal lesions. occur in the second trimester of pregnancy. Both endemic and Infected bulls rarely show clinical signs, and the organisms are epidemic abortion patterns have been described in cattle. In the routinely isolated from the prepuce and semen(9). Several recent endemic pattern, the herd experiences an elevated abortion rate of disease incidents suggest that pathogenic Ureaplasma strains are greater than 5% per year and this persists for years. The epidemic present in New Zealand cattle(10). Of particular interest has been the pattern is less common, and is characterised by a high incidence of presumptive diagnosis of Ureaplasma abortion in imported bovine abortions over a relatively brief period of time. In severe cases, over embryo transplants, as this may provide a route by which the 30% of cattle may abort, most within a few weeks though abortions organism could enter into a country. may continue over a period of several months(3),(4). In any one year, Miscellaneous bacterial and protozoal abortions: Bacteria that have approximately 20% of all bovine abortion submissions to Animal been isolated in pure growth from foetal stomach contents include Health Laboratories in New Zealand are diagnosed with Neospora Acarnobacterium (formerly Actinomyces) pyogenes, Aeromonas infection(5). species, Bacillus licheniformis, Haemophilus somnus, Streptococcus Fungal abortions: In New Zealand, most fungal abortions are due to species and Listeria species. Abortions caused by these organisms are either Mortierella wolfii or Aspergillus fumigatus infection. They have usually sporadic and of minor importance. Rare reports of abortion a distinct seasonal pattern, with most occurring between May and storms due to Listeria monocytogenes infection exist in the literature July. Mortierella abortion is usually associated with feeding of silage but no such outbreaks have been reported in New Zealand. with a higher than optimal pH. Aborting cattle may subsequently L ivanovii is a rare cause of sporadic abortions in cattle. L seeligeri develop a fatal mycotic pneumonia after haematogenous spread has been grown in pure culture from the placenta of an aborting from the placenta or uterus(6). M wolfii is a common fungus in cow fed silage(11) but it is not generally recognised as a cause of New Zealand but it is less frequently reported overseas. Aspergillus bovine abortion. 3.

page Surveillance 27(3) 2000 3 Abortions due to Trichomonas foetus may occur amongst beef cows isolates at LabWorks Animal Health Laboratory being resistant to in isolated regions of New Zealand but the disease has not been this antibiotic (DG Arthur, pers. comm.). found in dairy cows. The prevalence of coliform mastitis is increasing in New Zealand. Viral abortions: Bovine virus diarrhoea virus is the predominant About 10% of coliform infections cause peracute mastitis, requiring viral cause of bovine abortions in New Zealand. When cows are intensive therapy and veterinary intervention. The control methods infected with BVD virus in the first 100 days of pregnancy, abortion most widely used are less effective in controlling ‘environmental or mummification may occur at 3-5 months of gestation. No lesions group’ mastitis than they are for ‘contagious group’ mastitides. In are seen in freshly aborted foetuses but the virus may be detected well managed herds, in which S agalactiae and S aureus are usually in the spleen. Relatively few BVD abortions are diagnosed in controlled, mastitis caused by environmental bacteria may continue New Zealand despite the fact that about 60% of adult cattle have as a serious herd health problem. serological evidence of infection with the virus(12). However, the test S dysgalactiae is a quite common cause of mastitis that may behave is not routinely requested due to cost, so cases may be under- both as a ‘contagious group’ and an ‘environmental group’ reported. The strains of infectious bovine bacterium. It is readily controlled by teat spraying and dry cow rhinotracheitis virus appear not to be present in New Zealand. therapy but new infections can occur when there are no current Causes of mastitis intra-mammary infections present in the herd. Most cases of mastitis are caused by only a few types of bacteria - Other common mastitis pathogens: Some bacteria commonly staphylococci, streptococci and some gram-negative species. These inhabit the bovine udder but rarely cause clinical mastitis. These common pathogens fall into two categories: contagious bacteria that include coagulase-negative staphylococci and Corynebacterium bovis. are spread from infected quarters to other quarters and between These two are of interest because they are the most common types of cows, and environmental bacteria that are commonly present and bacteria that may remain in herds subjected to standard mastitis may enter the teat from that source. This distinction is of practical control, and their presence usually causes a 2 to 3-fold increase in importance because different control measures are needed for the somatic cell counts. two categories of bacteria. Uncommon mastitis pathogens: Microorganisms that cause Contagious bacteria: The common ‘contagious group’ bacteria are sporadic, severe individual cow or herd outbreak mastitis include Staphylococcus aureus and Streptococcus agalactiae, and their main Pseudomonas species (especially P aeruginosa), Acarnobacterium reservoir is the infected cow. However, S aureus also readily colonises pyogenes and Bacillus species. In reported outbreaks, P aeruginosa the teat canal and chapped or sore teat skin, and they may also infection was thought to have occurred whilst administering dry cow survive in other sites on the cow. In terms of chronic infection, therapy(16). Udder washing water and contaminated teat spray are S aureus is probably of greatest importance since, although of other possible sources of infection. P aeruginosa is resistant to most relatively low incidence (about 5% of clinical cases(13)), it persists in commonly used antibiotics. the udder and is highly infectious via milking machines. Subclinical A pyogenes can cause severe clinical mastitis characterised by a thick, infections associated with high somatic cell counts are common in purulent secretion. Infection often occurs following teat-end damage New Zealand dairy cows. The antibiotic resistance patterns of and usually results in loss of the quarter. Bacillus cereus is sometimes S aureus isolates vary within and between herds(13), but many are isolated from cows without clinical mastitis but with high somatic resistant to penicillin. Overseas, a staphylococcal vaccine has proven cell counts, and it can also cause a severe, necrotising mastitis(17). to be effective in reducing the rates of subclinical and clinical Clostridium perfringens has occasionally been isolated from cows mastitis in seriously affected herds(14), but such a vaccine is not yet with severe necrotising mastitis. B licheniformis is a rare cause available in New Zealand. of mastitis(18). Effective mastitis control programmes can eradicate S agalactiae Many other bacteria, yeasts and fungi have been reported as rare from individual herds, and reduce S aureus prevalence to very low causes of mastitis in New Zealand. These include Aeromonas levels in most herds. hydrophilia, Nocardia asteroides, and Candida, Aspergillus, Environmental bacteria: The most common ‘environmental group’ Pseudoallescheria and Trichosporon species. Diagnosis of these forms pathogens are Streptococcus uberis and coliforms, mainly Escherichia of mastitis is by culture from affected glands, and it may not be coli. S uberis is increasing in importance as a mastitis pathogen and is known whether they are pathogens or contaminants. Tuberculous responsible for approximately 70% of clinical cases in lactating cows mastitis has not been reported in New Zealand since the in New Zealand(13). It is also responsible for the majority of cases of implementation of the bovine tuberculosis eradication scheme. clinical mastitis in dry cows(15). Most isolates of S uberis are sensitive to a broad range of antibiotics, although this species is inherently Bacterial diseases resistant to streptomycin. Recent data indicate that a cloxacillin- Campylobacteriosis: Formerly called vibriosis, campylobacteriosis is resistant strain of S uberis is emerging in New Zealand, with 17% of a venereal disease of cattle caused by the bacterium Campylobacter

page 4 Surveillance 27(3) 2000 fetus subspecies venerealis. These bacteria are confined to the Transmission occurs primarily within the first few months of life by reproductive tract of cattle(19). Infection occurs at service, or during the faecal-oral route, but other well-recognised routes are artificial insemination with use of infected semen or equipment, and transplacental and in colostrum and milk fed to young calves. For a results in an endometritis that prevents conception or causes early large part of the pre-clinical stage, which lasts at least 18 months and embryonic loss. Bulls become infected after serving infected cows. often much longer, infected cattle harbour small numbers of Abortions occur in about 10% of exposed cows at 6-8 months of M paratuberculosis bacteria, and few are shed in the faeces. As the gestation. Campylobacteriosis is extremely rare in New Zealand infection progresses, more bacteria are shed and an antibody dairy cattle due to the widespread use of best-practice artificial response becomes more prominent. While it is probable that insemination. There have been only a few laboratory confirmed cases improved diagnostic tests will become available in the foreseeable of bovine genital campylobacteriosis in beef herds in New Zealand. future, adoption of management practices designed to minimise or Infection with C fetus subspecies fetus can cause severe placentitis eliminate exposure to the organism remains crucial in controlling and abortion. this economically and politically important disease.

Contagious bovine pyelonephritis: This is a specific infection of the There is no cure for Johne’s disease. A vaccine containing live urinary tract of cattle caused by Corynebacterium renale. Infections attenuated M paratuberculosis is available in New Zealand. However, are almost invariably sporadic. Pyelonephritis usually develops as an vaccination causes sensitisation to avian and mammalian tuberculin ascending infection involving the bladder, ureters and kidneys. and should not be used if the cattle are at risk from bovine Clinically affected or clinically normal ‘carrier’ cows are probably the tuberculosis. Also, lesions that may develop at the vaccination principal source of infection, since the disease is transmitted by site can closely resemble those of bovine tuberculosis(25). Thus, it direct contact or by careless use of catheters. It has been suggested is vital that animals vaccinated against Johne’s disease be that the disease can also be spread venereally. permanently identified.

Haemophilosis: Overseas and in New Zealand, Haemophilus somnus The possibility that Crohn’s disease is a zoonotic manifestation of is a common isolate from the vagina of cows and the prepuce of Johne’s disease has been debated recently but the consensus of bulls(20). It may also be present in semen. H somnus can not survive opinion seems to be moving away from this view. for long outside the body, and the reproductive tract is considered to Leptospirosis: Overseas, Leptospira hardjobovis infection in dairy be the most likely reservoir of this organism. In cows, H somnus cows is associated with abortion, mastitis and reduced production infection can cause vaginitis, endometritis, infertility and abortion. (‘milk drop syndrome’)(26). In New Zealand, L hardjobovis infection is The organism has been isolated from cows with a severe vaginal endemic in many dairy herds but the infection is mostly unapparent. discharge, but it has rarely been associated with abortions in New This may indicate a difference in virulence between New Zealand Zealand(20). Thromboembolic meningoencephalitis (TEME) caused strains and those overseas. Infection with L pomona can cause acute by H somnus has been diagnosed in New Zealand in feedlot cattle disease and abortions in adult animals. Leptospirosis is a zoonosis that have died after exhibiting neurological and respiratory signs(21). and is the most important communicable occupational disease in Infectious bovine keratoconjunctivitis (‘pink eye’): This disease is New Zealand(27). Serovars of significance to humans include L caused by infection with Moraxella bovis, and is the most common hardjobovis and L pomona, primarily from dairy cattle. Vaccination, and significant eye disease of adult cattle in New Zealand. A greater especially of dairy cattle, has been widespread in New Zealand and number of reported cases occur in the North Island during the has dramatically reduced the incidence of human leptospirosis(28). summer months(22). The bacterium Branhamella ovis is closely Listeriosis: In Listeria monocytogenes meningoencephalitis of adult related to M bovis and has been found in conjunction with M bovis cattle, the infection is often unilateral, and clinical signs include in cases of severe purulent keratoconjunctivitis. However, the facial paralysis, deviation of the head and walking in circles in the organism is considered to be of low pathogenicity(16). direction of this deviation. L monocytogenes may be associated with Johne’s disease: This notifiable disease, caused by Mycobacterium sporadic abortions. The acute septicemic form of listeriosis causes avium subspecies paratuberculosis, occurs throughout New Zealand depression, weakness, anorexia, emaciation and diarrhoea in some and mainly affects dairy cattle. The number of infected herds has animals. Infection with L monocytogenes is transmissible to humans risen significantly and all intensive dairying areas of the North Island through milk, milk products and meat(29), in which case it can cause and the West Coast of the South Island have a high prevalence of systemic and often fatal disease. infection(23). Infection in beef herds occurs throughout the country Salmonellosis: Several large outbreaks of Salmonella Typhimurium but with a much lower prevalence. and S Bovismorbificans infection have been reported in dairy cows After a prolonged incubation period, M paratuberculosis causes a in New Zealand(30),(31). Affected cows showed malaise, diarrhoea and chronic granulomatous enteritis manifesting as diarrhoea (often dysentery, and several died. Disease often occurs in the winter and is intermittent) and progressive weight loss over a period of weeks or associated with feed shortages and inclement weather. Salmonellosis months(24) despite a good plane of nutrition and a good appetite. in humans is essentially a food transmitted disease and not primarily

page Surveillance 27(3) 2000 5 a zoonosis, although animals with salmonellosis must be considered mature, animals and rarely lymphosarcoma. Once infected, cattle a risk(8). S Typhimurium is the most common serotype affecting remain virus carriers for life, and they develop a serological reaction humans, and it has been isolated in 58% of cases of salmonellosis in within a few weeks of infection. During the 1996/97 season, the New New Zealand(32). Zealand dairy industry started a national EBL eradication campaign.

Recently, S Brandenburg has emerged as a significant pathogen in The programme will operate over an 8 year period, with the aim of cattle, causing diarrhoea, dysentery and death. Serotypes, Enteritidis, industry freedom from EBL by 2005. It is based on herd screening, Saintpaul, Senftenburg, Infantis, Heidelberg, Havana and Hindmarsh then identification and culling of infected animals. have been sporadically isolated from cases of diarrhoea in cattle in Infectious bovine rhinotracheitis (IBR): In New Zealand, most New Zealand. infections with bovine herpesvirus 1 are subclinical or cause only Skin tuberculosis: This sporadic granulomatous disease with mild clinical signs. However, more severe disease may occasionally numerous acid-fast organisms in the skin, subcutis and superficial occur, with many animals in an affected herd showing signs of upper lymph nodes has been reported in cattle throughout New Zealand(24). respiratory tract infection accompanied by a significant drop in milk The agent has not yet been positively identified but it is assumed to production. It is mainly the 2-year-old dairy heifers which are be a saprophyte. Skin tuberculosis causes an immunological cross- affected but some older cows are usually affected as well. It is reaction with Mycobacterium bovis, and this can potentially cause assumed that New Zealand dairy cattle are not often exposed to the problems with the interpretation of the tuberculin test. virus until they enter the milking herd, at which time they may become infected by latently infected older cows. Udder impetigo (superficial pustular dermatitis): This impetigo- like condition is caused by S aureus infection, and it occurs on the The virus also causes pustular vulvovaginitis (IPV) and udder and perineum of dairy cows. balanoposthitis. The respiratory and genital forms of BHV-1 infection in New Zealand are apparently due to an identical virus, Viral diseases but the two diseases occur separately(6). Animals which develop Bovine herpes mammillitis: Infection with BHV-2 can cause a lesions of IPV or balanoposthitis often fail to seroconvert to IBR. vesicular, erosive dermatitis around the base of the teats and Pseudocowpox: Infection with this parapoxvirus initially causes spreading out to involve adjacent skin of the udder. Recently calved small vesicles on the teats and udder. Scab formation follows rupture cows show the worst lesions, and the infection may spread rapidly of the vesicles, and covers a granulating area of skin. After a few days, through the herd. the scabs are lost, revealing typical horse shoe shaped lesions. Bovine virus diarrhoea (BVD): In adult cattle, the results of Immunity to pseudocowpox is short-lived. The condition may infection with this pestivirus will vary depending on the virulence be seen at any time of the year and is transmissible to humans and biotype of the virus, the animal’s immune status and the stage of (‘milker’s nodule’)(8). pregnancy. Post-natal infection of naïve, immunocompetent cattle with BVD virus usually results in a clinically unrecognisable Fungal diseases infection, the development of neutralising antibodies and Aspergillosis: The fungus Aspergillus fumigatus is widespread in New subsequent elimination of the virus. Infection at mating can result in Zealand and occasionally causes disease. Well recognised as a cause markedly reduced pregnancy rates due to reduced conception rates of placentitis and abortion in cattle, it can also cause sporadic lesions and increased embryonic loss. This occurs irrespective of the in various organs such as lungs, brain, lymph nodes and udder(7). immune status of the animal. Following infection of a non-immune Mortierella: M wolfii infection is relatively common in cattle in the animal, the virus may cross the placenta and infect the foetus. If the North Island of New Zealand. In the South Island, as overseas, it is a foetus is infected during the first trimester of gestation it may be sporadic infection(7). When ingested by pregnant cattle, the fungus carried normally to term and be born as a persistently infected may spread haematogenously to the uterus and cause a mycotic animal. Foetal death and abortion may result if the foetus is infected placentitis and abortion. during the first and second trimester of gestation. Some also consider BVD virus to be the major cause of foetal mummification. Mucor/Absidia: Besides being sporadic causes of abortion, Mucor Congenital defects, such as cerebellar hypoplasia, may result if foetal and Absidia are reported to be among the secondary invaders in cases infection occurs from about 120-180 days of gestation. of mycotic rumenitis and enteritis in cattle, though they are rarely cultured(7). Enzootic bovine leucosis (EBL): Bovine leukaemia virus (BLV) is a lymphotrophic retrovirus present in cattle in many countries, Ringworm: Infection with Trichophyton verrucosum causes thick, including New Zealand(33). The clinical disease caused by this virus is crusty plaques mainly on the head and neck of young cattle. This commonly referred to as EBL. Only a few cases have been recorded common disease is usually self limiting but it may persist well into in New Zealand(34). The disease affects adult cattle and has a peak adulthood, particularly in immuno-compromised animals. incidence between 5-8 years of age. It is characterised by a non- Ringworm is an important mycotic zoonosis, but cattle are a minor neoplastic, persistent lymphocytosis in up to 30% of infected, source of dermatophyte infection in man(8).

page 6 Surveillance 27(3) 2000 Protozoal diseases Cysticercosis: Occasionally, Cysticercus bovis cysts have been found Neosporosis: In cattle, Neospora caninum-like organisms cause in beef carcasses at slaughter in New Zealand(41). There are no reports abortions and stillbirths, more commonly so in younger cattle. The of human Taenia saginata infestations having been contracted in parasite has been found in aborted foetuses in various parts of the New Zealand. Our cattle are presumed to have become infected after world and is a major cause of abortion in cattle in New Zealand(2). eating pasture contaminated by faeces from humans who contracted Serological evidence suggests that Neospora infection may only be the parasite overseas. found in some dairy herds in New Zealand, and that the majority of Fasciolasis: Fasciola hepatica is the only species of liver fluke found herds may be uninfected(35). in cattle in New Zealand(42). Acute fasciolasis is mainly seen in calves. It is not yet known how the parasite is introduced into herds, or how Chronic fasciolasis is due to the activity of adult flukes in the bile common horizontal transmission between cattle is compared with ducts, and is mainly seen in adult cattle. There is weight loss, the congenital (vertical) route. Once a cow is infected, she may pass decreased milk production, submandibular oedema and there may the infection to her offspring during each pregnancy, and her be diarrhoea or constipation. An abattoir survey undertaken in daughters may in turn infect their offspring. Most of the infected 1984-85 suggested that 13% of North Island cattle herds were offspring will appear normal, and only a small percentage will be infested with liver fluke(43). An ELISA liver fluke serological herd aborted or born alive with ataxia. Secondary abortion peaks do not screening test has been used in New Zealand from 1999, and from occur, confirming that aborting cattle are not infective to their this it appears that the prevalence of bovine liver fluke infection has herdmates(36). Neospora may also cause mummification and increased significantly since then. infertility, but these effects have yet to be investigated. Lungworm: Dictyocaulus viviparus is the only lungworm of cattle in Sarcocystosis: This disease is caused by a two-host protozoan New Zealand. Overseas, outbreaks in adult dairy cattle nearly always parasite that requires carnivores and ruminants as respective occur because either cattle have not been exposed to sufficient definitive and intermediate hosts. Sarcocystis infection is unusual, parasitic challenge in earlier life to provide adequate immunity, or but second trimester abortions may occur in cattle(37). However, there immunity has been lost as a result of a lack of re-infestation. The have been no confirmed clinical cases of sarcocystosis in New significance of lungworm in adult cattle in New Zealand is debatable. Zealand cattle (WAG Charleston, pers. comm.). To date, only one account of a confirmed outbreak of lungworm infestation in a dairy herd has been published(44). However, Theileriosis: Infection with Theileria orientalis was first diagnosed in lungworm infestation has been associated with severe respiratory 1984, and since then it has been diagnosed in the warmer areas of disease in adult cows in the Canterbury area recently (DG Arthur, New Zealand where the tick Haemophysalis longicornis, which is pers. comm.). presumed to be the vector, is found(38). Infection is benign and may be detected in immuno-suppressed animals. Ostertagiasis: Clinical disease is occasionally diagnosed in adult cattle in New Zealand that have severe diarrhoea. Opinion is divided Trichomoniasis: Infection with the protozoan parasite Trichomonas as to the value of the practice of drenching cows and as to the foetus results in infertility and causes early embryonic death, relevance of European and North American data to New Zealand, abortion, endometritis and pyometra(39). During the last half century, particularly in view of this country’s all-year grazing management. only a few cases of trichomoniasis have been reported in the New For those who advocate treatment, the favoured drenching times are Zealand literature, and the last definitive diagnosis of this venereally at drying-off and/or at around calving. Ostertagia and Cooperia transmitted disease was made amongst beef cattle in the Hawke’s species are the main nematodes targeted. A variety of production Bay/Gisborne regions in 1996(40). Venereally transmitted diseases are responses have been seen after anthelmintic treatment of dairy cattle rarely identified as a cause of infertility or disease in New Zealand in New Zealand(45). Some herds showed significant responses after cattle, although this could be due to inadequacies of investigation treatment, whereas others did not. Efficacies against Ostertagia rather than a real lack of importance. species (in particular the arrested type) have been greatly improved Rickettsial diseases with the introduction of the newer range of avermectin/milbemycin Eperythrozoonosis: Only three cases of infection with the pro- compounds, and significant production and reproduction responses karyotic organism Eperythrozoon wenyoni have been reported in have been reported in the popular farming press. New Zealand(38). Anaemia and intercurrent disease was associated Miscellaneous diseases with the parasitaemia in these cows. Nasal catarrh: In New Zealand, this condition is also known as Parasitic diseases bovine nasal granuloma or chronic granular rhinitis(46). This disease Endo- and ectoparasites were covered in Part 1 in the previous issue is common in dairy cows in the North Island, particularly Jerseys. It of this journal. Additional information is provided here on is a seasonal disease, flaring up in the summer and autumn, and cysticercosis, liver fluke, lungworm disease and ostertagiasis in producing multiple, focal, raised, granulomatous nodules in the adult cattle. rostral nasal cavity. The predominant signs are respiratory stertor

page Surveillance 27(3) 2000 7 and dyspnoea due to obstruction of air flow. There is strong evidence (7) Fairley RA. Invasive fungi in New Zealand livestock. Surveillance 25(2), that the lesions result from a chronic allergic reaction, with pollen, 19, 1998. fungal spores and pasture mites being the most likely antigens(47). (8) Hill FI. Zoonotic diseases of ruminants in New Zealand. Surveillance 21(4), There is anecdotal evidence that the prevalence of nasal catarrh in a 25-7, 1994. herd decreases after vaccination of young stock against IBR. (9) Hodges RT, Holland JTS. The recovery of ureaplasmas from the semen and However, there have been no controlled studies in New Zealand to prepuce of bulls. New Zealand Veterinary Journal 28, 89-90, 1980. investigate a possible relationship between IBR-virus infection and (10) Thornton RN, Wake HH. Ureaplasma in New Zealand dairy cattle. Surveillance the lesions of nasal catarrh. 24(3), 15-6, 1997.

Winter dysentery: This disease of unknown aetiology is (11) Anon. Review of diagnostic cases – July to September 1995. Surveillance characterised by an acute, apparently contagious, enteritis that 22(4), 3, 1995. occurs in epizootic fashion within a herd, usually during the colder (12) Littlejohns IR, Horner GW. Incidence, epidemiology and control of bovine months of the year. Adult dairy cows appear to be most susceptible. pestivirus infections and disease in and New Zealand. OIE Revue Overseas, coronavirus infection is implicated in the disease, whereas Scientifique et Technique 9, 195-205, 1990. in New Zealand Campylobacter jejuni is sometimes isolated from (13) McDougall S. Efficacy of two antibiotic treatments in curing clinical and faeces of clinically affected animals. The role of Campylobacter subclinical mastitis in lactating dairy cows. New Zealand Veterinary Journal 46, 226-32, 1998. species in enteric disease in cattle is uncertain since they can be isolated regularly from healthy cattle(19), which makes their recovery (14) Watson DL, McColl ML, Davies HI. Field trial of a staphylococcal mastitis difficult to interpret. Some Campylobacter species, including C jejuni, vaccine in dairy herds: clinical, subclinical and microbiological assessments. Australian Veterinary Journal 74, 447-50, 1996. have zoonotic potential. (15) Williamson JH, Woolford MW, Day AM. The prophylactic effect of a dry-cow Exotic diseases antibiotic against Streptococcus uberis. New Zealand Veterinary Journal 43, A number of important infectious diseases of cattle are exotic to 228-34, 1998. New Zealand, including the bacterial infections acute haemorrhagic (16) Shrubb O. Gram-negative glucose non-fermenting bacteria in New Zealand septicaemia (Pasteurella multocida), brucellosis (B abortus), livestock. Surveillance 25(3), 19, 1998. contagious bovine pleuropneumonia (Mycoplasma mycoides), Lyme (17) Parkinson TJ, Merrall M, Fenwick SG. A case of bovine mastitis caused by disease (Borrelia burgdorferi) and Salmonella Dublin. Important viral Bacillus cereus. New Zealand Veterinary Journal 47, 151-2, 1999. diseases exotic to New Zealand are cowpox, foot-and-mouth disease, (18) Graham C. Bacillus species and non-spore-forming anaerobes in New Zealand rabies, rinderpest and vesicular stomatitis. Pseudorabies (Aujeszky’s livestock. Surveillance 25(4), 19, 1998. disease) has now been eradicated. There is no serological or clinical (19) Loveridge R, Gardner E. Campylobacter fetus venerealis infection in cattle. evidence in New Zealand cattle of the arboviruses that cause Surveillance 20(4), 26-7, 1993. Akabane disease, bluetongue or ephemeral fever. There has been no (20) Howell J. Haemophilus somnus infections in cattle. Surveillance 18(2), evidence of the abortifacient strains of IBR (BHV1.2a). New Zealand 10, 1991. is also free from the blood-borne parasites which cause (21) Langdon SE, Hutton JB. Cattle diseases in a New Zealand feedlot. Surveillance anaplasmosis, babesiosis and trypanosomiasis, being also free from 25(4), 15-6, 1998. many of the vectors (ticks and biting insects) that transmit those (22) Harris RE, Cooper BS, Steffert IJ, Brice JS. A survey of bovine infectious parasites. There is no histopathological evidence of bovine keratitis (pinkeye) in beef cattle. New Zealand Veterinary Journal 28, spongiform encephalopathy in New Zealand(48). 58-60, 1980. (23) Staples P. An update on Johne’s disease in New Zealand. Surveillance 21(1), References 14-6, 1994. (1) Hellstrom JS. New Zealand is free from bovine brucellosis. Surveillance (24) Montgomery RH. Mycobacteria in New Zealand. Surveillance 26(1), 6-8, 1999. 18(1), 14, 1991. (25) Montgomery RH. Tuberculosis-like lesions in cattle. Surveillance 24(3), (2) Thornton RN, Thompson EJ, Dubey JP. Neospora abortion in New Zealand 19-20, 1997. cattle. New Zealand Veterinary Journal 39, 129-33, 1991. (26) Heath SE, Johnson R. Leptospirosis. Journal of the American Veterinary (3) Thornton RN, Gajadhar A, Evans J. Neospora abortion epidemic in a dairy herd. Medical Association 205, 1518-23, 1994. New Zealand Veterinary Journal 42, 190-1, 1994. (27) Baker M, Wilson N, Bates M. Occupational communicable diseases in New (4) Cox BT, Reichel MP, Griffiths LM. Serology of a Neospora abortion outbreak on Zealand. Communicable Disease New Zealand 93(7), 85-94, 1993. a dairy farm in New Zealand: A case study. New Zealand Veterinary Journal 46, 28-31, 1998. (28) Marshall RB.A nationwide experiment to control human leptospirosis by (5) Thornton RN. Bovine abortion diagnoses in 1995. Surveillance 23(4), vaccinating dairy cattle. Israel Journal of Veterinary Medicine 43, 271-6, 1987. 21-2, 1996. (29) George G. 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