Contemporary approach in diagnostics, prophylaxis and treatment of footrot in sheep

Abstract

Zarazna šepavost ovaca je hronično, infektivno oboljenje akropodijuma ovaca, ređe koza i divokoza, polifaktorijalne prirode, za koju se smatra i da je bolest lošeg menandžmenta u ovčarstvu. Poslednjih nekoliko godina se kao glavni uzročnik navodi Dichelobacter nodosus, raniji naziv Bacteroides nodosus. Sadejstvo sa nekoliko drugih saprofitnih i patogenih bakterija nije više toliko značajno u etiopatogenezi, već se smatra važnijim da se odredi virulentnost soja D. nodosus. Ukoliko je infekcija izazvana vrlo virulentnim sojem D. nodosus, oboljenje se naziva Contagiosus ovine digital dermatitis (CODD) i tok bolesti se često završava „izuvanjem papka” Brzom identifikacijom agensa može da se predvide klinički oblik oboljenja, tok i prognoza bolesti. Benigni soj agensa izaziva samo blagi do srednje virulentan laminitis, sa slabo izraženim interdigitalnim dermatitisom, kada je ispoljeno šepanje životinje, na jednu ili dve noge. Vrlo virulentni soj uzrokuje težak oblik infektivnog interdigitalnog dermatitisa, kao gnojno-nekrotičnog dermatitisa, sa značajnim oštećenjem rožine, uz izrazitio šepanje životinja. Zarazna šepavost ovaca je prisutna u skoro svim zemljama sveta, naročito u zemljama sa razvijenom ovčarskom proizvodnjom (Novi Zeland, Australija i UK), u kojima nanosi i značajne ekonomske štete. U našoj zemlji zarazna šepavost ovaca se uglavnom javlja u Raškoj oblasti, Istočnoj Srbiji i Vojvodini, ali u različitom procentu od stada do stada. Nastanku i rasprostranjenosti ovog oboljenja značajno doprinosi neredovna i nepravilna obrada papaka (važna zootehnička mera), kao i niz drugih predisponirajućih faktora kao što su meka i vlažna zemlja, loši klimatski uslovi (toplo i vlažno vreme). U preveniranju, odnosno profilaksi, kao i terapiji zarazne šepavosti ovaca koja je kompleksne prirode, bilo je pokušaja sa primenom različitih dezinficijenasa. Tako se u literaturi navodi a u praksi sprovodi, dezinfekcija sa 10 posto bakar sulfatom, 5-8 posto formalinom, kao i u poslednje vreme, cink sulfatom, kako u supstanciji u obliku praška, tako i u obliku rastvora (od 1o-2o% ZnS04), više puta, u različitim vremenskim intervalima. Za dezinfekciju papaka ima nekoliko preskripcija. Neka od ovih sredstava su se pokazala kao vrlo efikasna. Cink sulfat ima izvesne prednosti u dezinfekciji papaka: baktericidan je, dublje prodire u tkivo na mestu dejstva, štiti rožnati deo papka, manje je toksičan, ekološki je prihvatljiv (lakše rešiv za uklanjanje) i jeftiniji je od ostalih pomenutih dezinficijenasa. Upotreba antibiotika je opravdana samo kod pojedinačnih, izolovanih slučajeva i to u lečenju interdigitalnih dermatitisa, dijagnostikovanih na više nogu. Međutim, upotreba antibiotika širokog spektra u obliku spreja u interdigitalni prostor, pokazala se opravdanom i efikasnom. Imunoprofilaksa daje različite rezultate i uglavnom se primenjuje kod mladunčadi (šilježadi) i ovaca u ranom graviditetu. Samo redovna i stručna obrada papaka, upotreba dezinficijensa cink sulfata u obliku rastvora po utvrđenoj proceduri, primena antibiotika u retkim slučajevima, korišćenje pašnjaka na dobro dreniranim zemljištima i vakcinacija određenih kategorija životinja, mogu zajedno, da doprinesu efikasnoj eradikaciji ovog „upornog” oboljenja ovaca.

Footrot in sheep is a chronic, infectious disease of the acropodium in sheep, less frequently in goats and mountain goats, of a multifactor nature, which is also considered to be a disease of poor management in sheep breeding. Over the recent years, Dichelobacter nodosus is given as the main cause, previously known as Bacteroides nodosus. Coaction with several other saprophytic and pathogenic bacteria is no longer so significant in etiopathogenesis, and it is considered more important to determine the virulence of the strain D. nodosus. The disease is called contagiousus ovine digital dermatitis (CODD) if the infection was caused by a very virulent strain of D. nodosus, and the disease often ends with the so-called removal of the foot. A speedy identification of the agent can provide insight into the clinical form of the disease, its course and predicted outcome. A benign strain of the agent causes only a mild to medium virulent laminitis, with poorly expressed interdigital dermatitis, when the animal openly limps on one or two legs. A very virulent strain leads to a grave form of infectious interdigital dermatitis, as a supurous-necrotic dermatitis, with significant damage to the bone and expressed limping of the animal. Footrot is present in sheep in almost all countries of the world, in particular in countries with a developed sheep production (New Zealand, Australia and the United Kingdom), where it causes significant economic damages. In our country, footrot in sheep occurs mainly in the Raska district, eastern Serbia and Vojvodina province, but the percentage varies from herd to herd. The irregular and incorrect processing of hoofs (an important zootechnical measure) significantly contributes to the occurrence and spreading of this disease, as well as a series of other contributing factors, such as soft and moist earch, bad climatic conditions (warm and humid weather). In activities on prevention and prophylaxis of this disease, as well as the treatment of footrot in sheep, which is complex in nature, there have been attempts to apply different disinfectants. For instance, disinfection with 10% copper sulphate, 5-8% formalin, as well as, more recently, zink sulphate, either in the form of a powder or as a solution (from 10-20% ZnSO4), several times during different time intervals, are recommended in litera ture and are being implemented in practice. There are a number of prescriptions for disinfection of hoofs and some of them have been shown to be very efficient. Zink sulphate has certain advantages in hoof disinfection: it is a bactericide, it penetrates deeper into the tissue in the crucial spot, it protects the horny part of the hoof, it is less toxic, ecologically acceptable (more readily disposable), and less expensive than other mentioned disinfectants. The use of antibiotics is justified only in individual isolated cases, in the treatment of interdigital dermatitis diagnozed on several legs. However, the application of widespecter antibiotics sprayed into the interdigital space has proven justified and efficient. Immunoprophylaxis yields different results and is mostly implemented in lambs and sheep in early stages of gravidity. Only regular and expert processing of hoofs, using a zink sulphate disinfectant in the form of a solution according to a prescribed procedure, the use of antibiotics in rare cases, putting animals to pasture in well-drained soil, and vaccination of certain categories of animals can all significantly contribute to the efficient eradication of this persistent disease in sheep.