Hemorrhagic Bowel Syndrome of Fattening Pigs in Kathmandu Valley

An outbreak of disease was reported between April to June 2010 affecting pigs raised in and around Kathmandu Valley primarily from the age group of 3 to 4 months . A total of 346 deaths in a herd of 1056 pigs were reported. Pigs on the affected styes were mostly fed with stale left-overs from hotels restaurants with food consisting of rice, meat, fish, vegetables, and left over desserts, all cooked in heavy oils. After consuming such (swills) from kitchen waste garbage the pigs started showing symptoms such as diarrhea and swaying gate movement, both of which were treated with antibiotics without recovery being detected.

Clinical and post-mortem examination of Herds:

Clinical history, as reported by owners, revealed limited information regarding the sudden death of one or several pigs within the three months. However, the association with the hotel restaurant left-over waste feeding was common. The pigs that died were in excellent conditions, but extremely pale. The blood was thin and watery. A significant increase in cases of HBS was seen during spring and early summer. An affected pig was often one of the healthiest pigs, only to be found dead later without warning. The pigs became bloated unusually quickly after death. The intestines were found to be filled with gas and blood wads when observed at necropsy. The small intestines contained bile-stained mucus to the level of mid-ileum where the hemorrhages began and became gradually more copious with large blood clots in the terminal ileum. The ilea mucosa was thickened and irregular due to corrugations involving the entire circumference and oriented in both transverse and longitudinal planes. The large intestine contained a great deal of clotted blood which appeared to have been passed from the ileum. The terminal jejunum and entire ileum had thick corrugated mucosa and large intraluminal blood clots. Cecum, colon and rectum contained dark, tarry blood which was similar to report of W. D. G. Yates, E. G. Clark, A. D. Osborne, C. C. Enweani, O. M. Radostits, and A. Theede. The condition has no definitive lesions, and the stomach was often found to be filled with feed.

Necropsy revealed that the entire intestinal tract had a severely congested, thin-walled appearance. Intestinal contents were usually watery and contained unclotted brownish blood. The condition differed from gastric ulcers, gastrointestinal torsion or volvulus, and from the hemorrhagic form of proliferative enteritis that was similar to earlier reports in vetmed.iastate.edu/.../miscellaneous-lesions -.

Laboratory examination of feed sample and post-mortem tissue samples

Samples of swills of different lots and post-mortem tissue samples in mycobioal culture media revealed the growth of penicillum spp, which was similar to the findings of Karki et.al.2008.

Treatment and prevention attempted

Based on clinical observation all the pigs in affected styes that were treated with toxin binder Varishta and BMD mixed in with swill as well as Lactoline Tylosin and Chlortetracycline antibiotic mixed in with water resulted in the condition subsiding subsequently within 7 to 15 days

Review of literature

Hemorrhagic Bowel Syndrome has been reported from the United Kingdom, United States, Taiwan, Australia and Europe. Reports from other countries indicate that cases occur elsewhere as well. The condition is well known to veterinary pathologists in Canada but has not been formally reported. The suggested causes for the unexplained hemorrhagic enteropathies seen in swine have been numerous, including hypersensitivity reactions to Escherichia coli antigens or to whey proteins, clostridial or coliform enterotoxaemia, mycotoxins, Vitamin E deficiency, mesenteric torsion, indigestion leading to gaseous distension and shock, genetic predisposition and or clotting defects and stress.

However, in the specific case of Hemorrhagic Bowel Syndrome, the strongest correlation is found with the presence of the bacterium Campylobacter sputorum subspecies mucosalis in affected areas. There has been some success in reproducing the condition experimentally, using intragastric administration of this organism and homogenized intestinal mucosa from pigs with adenomatosis (W. D. G. Yates, E. G. Clark, A. D. Osborne, C. C. Enweani, O. M. Radostits, and A. Theede). 

It's also called the stealth bomber of swine disease. It strikes suddenly, without warning. It kills quickly, often taking the best pigs and frequently leaves the producer wondering what struck the herd. Hemorrhagic bowel syndrome (HBS) is an unpredictable medical condition of swine. Its major cause is unknown but is likely a combination of many things, including genetic predisposition, irregular diets or feeding schedules, and high summer temperatures. HBS most often occurs in finisher/market pigs over 160 lb, so the economic costs of HBS can be very high with even a few affected pigs even though mortality is usually around 2%.

An affected pig is typically one of the best performing pigs and is only later to be found dead without warning. The hog may become bloated after death with unusual speed, and intestines filled with gas and blood may be observed at necropsy. The condition has no definitive lesions, and the stomach can often be filled with feed. Outbreaks may last from 7 to 10 days, and often occur in waves in which several pigs are affected.

The herd is seemingly otherwise healthy until the next wave. Similar to the bloody form of proliferative ileitis, stool may be dark, tar-like, or bloody. Severe bleeding into the intestine often resulting in sudden death is common as well as blood filled loops in the small intestine. Thinning of the small intestinal wall with no proliferation of intestinal cells is seen as well. Bowel syndrome (HBS) causes the sudden death of 4-6 month-old fattening pigs (70-120kg). Usually, there is no clinical or pathological previous history, nor warning signs that could alert the farmer. In most of the cases, the weight and health conditions of the affected animals are perfectly normal.

As a result, the diagnosis of HBS is mainly done post-mortem. HBS can account for up to one-third of total fattening mortality. Hemorrhagic bowel syndrome is such defined due to the low prevalence and inability to target one specific disease process or organism as the contributor to the syndrome.

From all above findings and observations,  it is concluded that during climate changes from cooler to hotter humid summer seasons in tropics there is likely to be an increase in fermentation in swill, which mostly contains grains, heavy fat and protein, in hotel and restaurant waste. Further humid and hot weather conditions favor the mold growth and putrification of left-over waste. This leads to the formation of mycotoxin and endotoxin, which is detrimental to livestock, poultry and pigs. If these feeds are fed untreated there is likely to be an increase in the mortality rate of these animals.

References

• Häni H, Zimmermann W, Huber A, Schmidt J The "hemorrhagic bowel syndrome" of swine: clinical, pathologo-anatomic and etiopathogenic aspects.Institut für Tierpathologie, Universität Bern. Schweiz Arch Tierheilkd. 1993;135(4):117-24. www.ncbi.nlm.nih.gov/pubmed/8506473
• Understanding and Managing Sudden Death in Fattening Pigs DuringSummer:www.thepigsite.com/.../understanding-and-managing-sudden-death-in-fattening-pigs-during-summ...
• William L. Hollis, B.S., D.V.M., Carthage A Veterinarian's Perspective Will Nutrition and Management Stop Hemorrhagic Bowel Syndrome? Veterinary Service, Ltd. Professional Swine Management, LLC, IL, USA and published in the Midwest Swine Nutrition Conference 2006. www.thepigsite.com/.../pig.../will-nutrition-and-management-stop-hemorrhagic-bowel-syndrome.
• W. D. G. Yates, E. G. Clark, A. D. Osborne, C. C. Enweani, O. M. Radostits, and A. Theede Can Vet J. 1979 October; 20(10): 261-268. PMCID: PMC1789606 Proliferative Hemorrhagic Enteropathy in Swine: An Outbreak and Review of the Literature: www.ncbi.nlm.nih.gov › Journal List › Can Vet J › v.20(10); Oct 1979
• Miscellaneous Lesions, Conditions, and Syndromes | Iowa State ... vetmed.iastate.edu/.../miscellaneous-lesions -
• Hemorrhagic bowelAlpharma:alpharmaswine.com/.../HMBS_enteric.html
• Growing/Finishing Diarrheal Diseases:www.ces.purdue.edu/.../gigf.htm
• Kedar Karki and Purnima Manandhar: ClinicalEpidemiologicalInvestigation of Mouldy Corn Poisoning due to Penicillium spp. in mules at Udayapur District, Nepal: Veterinary World pp 107-110 vol. 1 no. 4 April 2oo8

Acknowledgment

We would like to thank Dr. Ram Krishna Khatiwada, Program Director of Directorate of Animal Health, Tripureswor Kathmandu for providining early indications of this problem. Thanks are due as well to Mr. Bal Bahadur Kunwar, Mr. Tek Bahadur, Air Senior Vet. Technician, and Mr.Bhimsen Adhikari Vet. Technician of Microbioly Unit, Mr. Purna Maharajan Vet Technician of Central Veterinary Laboratory for doing the microbiology and post-mortem studies and to office assistant Mr. Chandra Bahadur Rana for his tireless effort in handling the carcasses during post-mortem work.