PARAPOXVIRUSES IN DOMESTIC LIVESTOCK IN NEW ZEALAND

Introduction only cattle less than two years old are affected and in There are four types of common parapoxvirus causing this age group the morbidity can reach 100 percent. infections in domestic livestock. They include bovine Lesions are characterised by multiple circular papules papular stomatitis virus (BPSV), orf virus (contagious or erosions up to 15 mm in diameter on the mouth, pustular dermatitis or CPD) and pseudocowpox virus, muzzle, nasolabium, teats, and rarely on the oesophagus which is very closely related and possibly identical and rumen. Lesions expand and may coalesce, becoming to BPSV (Munz and Dumbell, 2004). In addition, slightly depressed with a greyish-brown necrotic centre. parapoxvirus of red deer is considered to be a separate Lesions are not generally seen on the tongue. Diagnosis Parapoxvirus species (Robinson and Mercer 1995; is based on clinical signs, histology, electron microscopy Scagliarini et al., 2011). All parapox viruses are potentially and molecular tests. Serology is of limited value. zoonotic, causing nodular skin lesions usually on the fingers, hands or arms. Parapoxvirus infections are CASE EXAMPLE OF BPS IN CATTLE common in sheep, goats and cattle in New Zealand Eight of 48 calves (17 percent) were affected with a variety (Horner et al., 1987). Reports of disease in deer since 1985 of oral lesions. On further examination, their general suggest it is now relatively common in this species too demeanour was normal, with no drooling, lip smacking, (Horner et al., 1987; Smith et al., 1988; Hilson, 1997). or lameness present, but the affected calves were mildly pyrexic (rectal temperature > 40oC). In cattle bovine papular stomatitis (BPS) is a common endemic disease that can be confused with vesicular There was some variation in the oral lesions. Most were disease. Vesicles and scabby lesions arising from papules (4–5 mm high and 4–5 mm in diameter) present pseudocowpox may also present similarly to those of on the underside of the tongue (Figure 1). Periodontal vesicular disease or lumpy skin disease. Contagious reddening was also present in the oral cavity. On the pustular dermatitis is unlikely to be confused with muzzle and inner lips some of the lesions had coalesced to vesicular disease in sheep. The main exotic differential become ulcerated with peripheral reddening (Figure 2). for parapoxvirus in red deer is cervid poxvirus, but Other animals present on the farm were unaffected, this disease has only been identified in mule deer and including another management group of 42 calves and the reindeer. Skin lesions for cervid poxvirus are generally dairy cow herd. a lot more extensive, with potentially some systemic A biopsy was collected from the papular lesions of one of involvement. the affected calves. A portion of the tissue collected was The key points of New Zealand parapoxviruses are fixed in 10% buffered formalin and the remainder left summarised below, along with relevant case examples. unfixed for molecular testing. Histological examination revealed a proliferative and erosive dematitis. Epithelial Bovine papular stomatitis (BPS) cells at the margins of lesions contained eosinophillic intracytoplasmic droplets consistent with poxviral Positive diagnoses of BPS are made from time to time at inclusions. The fresh tissue tested positive by PCR for the Investigation Diagnostic Centre during investigations Parapoxvirus. Nucleotide sequences had an identity of to exclude vesicular disease. Clinical disease is typically 99 percent homology to BPSV sequences in the GenBank seen in young cattle, with stress likely to exacerbate the database. condition. Clinical expression of the disease varies and sometimes it is asymptomatic. In a recent investigation into herpesvirus-associated respiratory disease, BPSV was Pseudocowpox detected in two of 23 calves (9 percent) without noticeable The presence of pseudocowpox in New Zealand was oral lesions, using virus isolation and PCR from nasal confirmed in 1968 and at the time it was considered to swabs. In another case clinical signs in calves initiated a be relatively common in cattle (Carter et al., 1968). The vesicular investigation, and this is detailed below as a case incubation period is about six days. In a naïve herd the example. disease will present as a rapidly spreading acute outbreak. Lesions begin as papules on the teats (rarely the udder) The incubation period of BPS varies from 3–7 days and that progress to crusting with a characteristic horseshoe- in the early stages there may be a mild fever. Generally, shape spread out to 15–20mm in width. Generally,

14 SURVEILLANCE 39 (2) 2012 however, all that is recognised are varying degrees of mild Parapoxvirus of red deer teat ulceration and scab formation as lesions heal over Until recently parapoxvirus in red deer had only been a six-week period. Infection is transferred from cow to reported in New Zealand but recently an outbreak was cow by mechanical transfer and potentially from cow to reported from Italy (Scagliarini et al., 2011). In this case calf by suckling, Pseudocowpox lesions on the teats of severe oral ulceration and erosions were present, in cows have not been a common initiator of exotic disease contrast to the New Zealand syndrome where clinical investigations. signs are generally mild. TheParapoxvirus species found in red deer is considered to be distinct from the other parapoxviruses (Robinson and Mercer, 1985; Moerdyk- Schauwecker et al., 2009). Disease in New Zealand red deer is characterised by scabby lesions on the muzzle, lips, face, ears, neck and velvet (Horner et al. 1987). Disease is more common in younger animals (< 2 years), with morbidity often reaching 100 percent. Diagnosis is generally made on clinical signs alone, but histology, electron microscopy and molecular tests may also be useful. CASE EXAMPLE OF PARAPOXVIRUS IN RED DEER Tis outbreak occurred during the period of velveting (December 2011) and resulting in most of the ~200, two-year-old stags in the two management groups being Figure 1: Papules caused by bovine papular stomatitis virus on the ventral surface of the tongue of a six-month-old calf. (Photo: Chris Ward, Kaitaia affected to varying degrees Figure( 3). Vets). The surface lesions on the velvet were characterised by thick serocellular crusts. Histologically these crusts contained massive numbers of degenerate polymorphs, sometimes extending into hair follicles.

Figure 2: Erosive lesions on the nasal planum of a six-month-old calf Figure 3: Multiple circular raised erosive lesions on the velvet of a 2-year caused by papular stomatitis virus. (Photo: Chris Ward, Kaitaia Vets). old stag, caused by parapoxvirus of red deer. (Photos: Dougall McLauglin, Waimate Vets).

SURVEILLANCE 39 (2) 2012 15 The morphological diagnosis of lesions was subacute REFERENCES proliferative dermatitis with ballooning degeneration. Hilson R (1997) A different approach to handling a parapox outbreak in Parapox virus of red deer was confirmed by PCR and young velvet stags. Proceedings of the Deer Branch of the New Zealand electron microscopy. Veterinary Association 14, 251–254. Horner GW, Robinson AJ, Hunter R, Cox BT, Smith R (1987) Parapoxvirus Contagious pustular dermatitis (CPD) infections in New Zealand farmed red deer (Cervus elaphus). New Zealand Veterinary Journal 35, 41–45. This condition is commonly referred to as scabby mouth, and is most often seen in lambs as crusting, proliferative Smith R, Orr MB, Cox BT (1998) Scabby skin lesions in deer, with particular reference to parapoxvirus disease. 15(2), 18–19. lesions around the mouth and nose; more rarely on the Surveillance coronary band and interdigital areas of the feet. Transfer Robinson AJ, Mercer ]AA (1985) Parapoxvirus of red deer: evidence for of infection to lactating ewes may occasionally cause its inclusion as a new member in the genus Parapoxvirus. Virology 208, 812–815. lesions on the udder. This is the only parapoxvirus in New Zealand against which active vaccination is carried Scagliarini A, Vaccari F, Turín F, Bianchi A, Cordioli P, Lavazza A (2011) Parapoxvirus Infections of Red Deer, Italy. Emerging Infectious Diseases 17, out. A three-year study in the early 1980s reported that 684–687. about 0.5 percent of lambs slaughtered at meat processing Moerdyk-Schauwecker M, Eide K, Bildfell R, Baker RJ, Black W, Gram D, plants had CPD lesions, with the highest incidence in Thompson K, Crawshaw G, Rohrmann GF, Jin L (2009) Characterization of December and January (Robinson, 1983). In this study Cervidpoxvirus isolates from Oregon, California, and eastern Canada. Journal the percentage of affected lines was greater in the South of Veterinary Diagnostic Investigation 21, 487–492. than the North Island. Factors that may be important in Robinson AJ (1983) Prevalence of contagious pustular dermatitis (orf) in promoting disease include dry conditions, the presence six million lambs at slaughter: a three-year study. New Zealand Veterinary of prickly plants, and management that promotes animal Journal 31, 161–163. contact and causes damage to the skin (e.g., tailing and Carter ME, Brookbanks EO, Dickson MR (1968) Demonstration of a ear-tagging). pseudo-cowpox virus in New Zealand. New Zealand Veterinary Journal 16, 105–108. The condition is easily recognised by both farmers and veterinarians and few cases of CPD have been diagnosed Munz E and Dumbell K (2004) Pseudocowpox. In: Coetzer J, Tustin R (eds). Infectious diseases of Livestock. Pp. 1689-94. Oxford University Press, as part of exotic disease investigations. Capetown, South Africa. Discussion The parapox viruses form a group of endemic viruses Andrew McFadden some of which are important differentials for exotic Investigation and Diagnostic Centre vesicular diseases such as foot-and-mouth and Ministry for Primary Industries vesicular stomatitis. In general, parapox lesions can be [email protected] differentiated from the exotic vesicular diseases by their superficial nature, the absence of vesicle formation, and Thomas Rawdon Investigation and Diagnostic Centre non-systemic presentation with little or no pyrexia. BPS Ministry for Primary Industries is, however, of particular relevance as it may present [email protected] with multiple circular oral papules or erosions that can coalesce to develop depressed, necrotic centres. BPS is a more common initiator of calls to MAF from veterinarians concerned about the potential presence of an exotic vesicular disease.

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