Prevalence and Etiology of Abscess Disease of Sheep and Goats at Qassim Region , Saudi Arabia

Abscess disease (caseous lymphadenitis and Morel disease) is a worldwide contagious bacterial disease of sheep and goats and is adversely affecting the development of the sheep industry in Saudi Arabia. Fifteen sheep and 12 goat farms at Qassim region, central Saudi Arabia, were surveyed during September and October 2008 for the determination of the prevalence and the etiology of abscess disease. One hundred and twenty pus samples were collected from affected external lymph nodes of clinically-ill sheep and goats and from infected internal lymph nodes and organs condemned during meat inspection in the slaughterhouses, for the isolation and identification of pathogenic bacteria causing sheep abscess disease. The prevalence of abscess disease varied between 5%– 44.1% in sheep farms, being highest in the Najdi breed, and between 2.2 % – 6.5 % in goat farms. Males of both sheep and goats had the highest rate of infection compared to females (p <0.01). Bacterial isolates were obtained from 97 out of the 120 collected pus samples (80.83 %). The remaining 23 samples were sterile. Corynebacterium pseudotuberculosis and Staphylococcus aureus subsp. anaerobius accounted for about 54% of isolates, with almost equal frequencies (p =0.5). Other pyogenic bacteria such as S. aureus, Streptococci, Pseudomonas aeruginosa, Actinomyces pyogenes were also isolated from infected abscesses. They represented about 46% of the isolated etiological agents of sheep abscesses. This explains why available vaccines (bactrins) against caseous lymphadenitis (CLA) are poorly protective against abscess disease in Saudi Arabia.


Introduction
The losses caused by CLA may become important when its prevalence is high, particularly in countries Abscess disease, commonly known as Morel's with large numbers of sheep such as Australia.The disease and caseous lymphadenitis (pseudolosses are caused by condemnation and downgrading tuberculosis) deserves interest because of its of carcasses and skin in abattoirs as well as reduction contagious nature, worldwide distribution and lack of in wool growth (Paton et al., 1988(Paton et al., , 1994;;Williamson, effective control measures.It is primarily a disease of 2001).sheep and goats, and once introduced into a flock, it is Previous studies (Paton et al., 1988; De la Fuente very difficult to control because of its poor response to et al., 1997) have indicated spread of CLA mostly treatment, its ability to persist in the environment and occurred around the time of shearing.Several modes the limitations in detecting subclinically infected of transmission of CLA during shearing have been animals (Ivanovic et al., 2009;Williamson, 2001).suggested and there are evidence incriminating the Morel's disease is caused by Staphyloccocus aureus lungs in the transmission of the disease (Ellis et al., subsp.anaerobius, that exists as a single bacterial 1987).Corynebacterium pseudotuberculosis was clone worldwide (de la Fuente et al., 2010;Elbir et al., isolated from the tracheae of sheep with lung 2010).Caseous lymphadenitis is characterized by abscesses, which indicated that the lung transmits formation of abscesses in external and internal lymph CLA through aerosol contamination of skin cuts of Corynebacterium uninfected sheep.nodes and is caused by pseudotuberculosis (Baird and Fontaine, 2007).Some There is no available vaccine that is known to sheep breeds were found to be more susceptible to the confer solid immunity against Abscess disease.
Production of effective vaccines targeting known disease than others (Pepin et al., 1988).
C. pseudotuberculosis antigens is advised (Dorella et taken to the laboratory for bacterial cultivation and al., 2009).In some countries where vaccines are identification.The origin and number of collected pus available, vaccination failure is blamed on improper samples is given in Table-1 et al., 2003).
contamination.The external surface of the affected Abscess disease is endemic in Saudi Arabian lymph node was wiped with 70% alcohol before sheep and goat farms, and despite genuine efforts to collection to avoid external contamination.The pus control it by vaccination and culling, its prevalence contents were aspirated using sterile 20 ml syringe remained high.Sheep farmers complain of poor with wide gauge needle.After collection, samples response to available vaccines (killed formalized were labeled and taken to the laboratory within 1-3 bacterins).The disease is threatening the development hours. of the sheep industry in the Kingdom mainly because Different media were prepared and sterilized of the low sale value of infected sheep in the market according to the manufacturer instructions.Blood was especially during Hajj (annual Muslim pilgrim to collected for the preparation of blood agar medium, Mecca) period.This paper describes the prevalence under strict sterile conditions, from the jugular vein of and etiology of abscess disease of sheep and goats in a healthy sheep with no history of abscesses or Qassim region, central Saudi Arabia.
vaccination.Collection was performed using acid citrate dextrose (ACD) blood collection bags.Blood Each pus sample, collected in a syringe, middle of the Arabian desert where sheep, goats and was put into a sterile plate, and a sterile cotton swab camels are the main livestock in the area.was used to mix the sample thoroughly.Pus was then Occasionally, small amounts of rain falls during streaked onto brain heart infusion agar plate winter leading to growth of annual pasture for grazing supplemented with 10% sheep blood.Similarly, a animals.Animals are either kept by nomadic Bedouins swab was taken from the edge of the lesion very close or in intensively producing modern farms.to the abscess wall followed by streaking the swabs The purpose of the survey was to collect basic onto the surface of blood brain heart infusion agar information on the epidemiology and etiology of plate supplemented with 10% sheep blood.o abscess disease in the area following complaint of Inoculated plates were incubated at 37 C and farmers about the increasing spread of abscesses in checked for growth daily for up to 5 days.An their sheep and goats flocks and also about the poor additional plate was inoculated with each sample and response to vaccination against abscess disease.incubated anaerobically using the Oxoid Gas-Pak jar Fifteen sheep (one in the animal market) and 12 goat and anaerobic environment-bearing envelope for flocks in intensively producing farms were surveyed isolation of S. aureus subsp.anaerobius.for the prevalence of abscesses in relation to breed, age Identification of the isolates: Bacterial colonies and sex of affected sheep and goats.
were identified on the bases of colonial, morpho-Microbiological studies: One hundred and twenty logical and characteristics as well as biochemical pus samples were collected from sheep and goats with activities (Quinn et al., 1994;Carter and Wise, 2004).clinical abscesses as well as from infected lymph Smears were prepared from each colony type and nodes condemned during meat inspection in stained with Gram's for microscopic examination.slaughterhouses.Intact swollen lymph nodes were Different isolates were then preserved in semisolid Systems, MD, USA).S. aureus subsp.anerobius were Among goats, the disease was found in 4 out of identified by its anaerobic growth on blood agar and 12 flocks (Table -3) and then only few individual negative mannitol fermentation and positive maltose animals were affected.Nine goats were recorded with fermentation with acid production.Corynebacterium abscesses out of 572 examined goats, the prevalence psudotuberculosis were identified using API®coryne being about 1.57 %.Prevalence was highest in flocks strips according to the manufacturer instructions mixed with sheep or when the general health of the concerning culture preparation, inoculation, and flock was poor.interpretation (bioMerieux®SA, Lyon, France).Each of Pseudomonas aeruginosa isolates was based on its production of greenish exopigments and oxidase enzyme detected by freshly prepared 1% α-naphthol in 95% ethanol and a 1% aqueous solution of paminodimethylaniline oxalate.Arcanobacterium (Actinomyces) pyogenes was characterized by its beta hemolytic glistening colonies after 48 hours on blood agar.On biochemical testing, A. pyogenes was positive for gelatinase and negative for both catalase and nitrate reduction tests.Statistical analysis: Results, where applicable, were Bacteriological results: Bacterial isolates were analysed for the level of significance between means obtained from 97 out of the 120 collected pus samples using a computer-adapted statistical programme, (80.83 %).The rest of the samples were sterile.Table - shows the frequency of bacterial isolates from sheep and goat abscesses.Pure cultures of S. aureus were

Results
isolated from 12 samples (12.37 %) while S. aureus Survey Results: The results of the survey for sheep subspecies anaerobius was isolated from 25 samples abscess disease are shown in Tables -2.(25.77 %).Pure cultures of C. pseudotuberculosis were isolated from 27 samples (27.84 %).Streptococci . Pus samples were implementation of CLA vaccination program (Paton collected from intact abscesses only to avoid external brain heart infusion agar base (Difco) o Survey: A survey was conducted during Septemberafter autoclaving and cooling down to ~ 50-55 C and October 2008 for the detection of the rate of infection the medium was poured into sterile plastic Petri plates with abscess disease in sheep and goat farms at Qassim after mixing.region, central Saudi Arabia.Qassim region lies in the Cultivation:

Table - 1. The origin of pus samples from sheep and goat abscesses used for bacterial isolation brain
heart infusion agar for further studies.Catalase two months of age and in adult sheep to up 3 years.positive S.aureus isolates were confirmed with Males had the highest morbidity rate (68 %) compared BBL™ Staphyloslide™ Latex Test (BD Diagnostic to females (32 %).

Table - 3. Prevalence of abscess disease among strip
contained 20 tests plus catalase which was goats

Table - 2. Prevalence rate of Abscess disease in 15 sheep flocks in Qassim region
Results on prevalence of abscess disease in University.The technical help of Dr. Mahmoud sheep in Qassim region and the highest prevalence of Hashad is highly appreciated.the disease in the Nadi breed conforms with many