One of the most serious diseases affecting pigs is the dreaded porcine dysentery (PD), this is a muco-hemorrhagic diarrheal disease. It is an infectious pathology with an acute course caused by Brachyspira hyodysenteriae (Gram-negative, anaerobic, highly mobile spirochete).
Characteristics.
It is characterized by presenting with muco-hemorrhagic diarrhea, in addition to producing lesions in the large intestine. If it is not adequately controlled, it subsequently evolves into a chronic process, with continuous recurrences. In acute courses, it can cause up to 50% mortality.
This bacterium has great variability of strains, present in pig farms. Each strain has different virulence factors (hemolysins, flagellar mobility and membrane lipopolysaccharides), greater or lesser resistance to antibiotics, its incubation period, its propagation capacity and its resistance to external agents and the environment.
Currently, it is one of the most serious problems in pig farms worldwide, due to the severity of the acute process and the high indirect losses it causes when it acquires an enzootic nature. This disease can mean a 20% increase in production costs, with growth lag, delays in dispatch to the slaughterhouse of up to 1 month and increases in conversion rates of up to 0.80 points. In recent studies in the USA, the productive loss in a fattened pig with dysentery has been valued at approximately $16.5/pig (J.Waddilove, 2011), including medication costs, increased mortality, non-marketable animals, lack of homogeneity , extra days of baiting and increased medication costs.
The resistance of the bacteria in the humid environment of the farm (up to 70 days at 10ºC, 7 days at 25°C and only 24 hours at 37°C), makes DP one of the most problematic and difficult to eliminate. Furthermore, the bacteria can colonize and reproduce in the intestine of other species temporarily and without clinical symptoms, such as mice (excretion for 6 months), rats (excretion for 2 days), dogs (13 days) and birds such as starlings (8h). Flies can act as vectors. It is for this reason that its control is a key point in any plan to eradicate this disease.
Transmission.
The infection occurs through the fecal-oral route.
1- Horizontal transmission.
This is the infection among pigs with subclinical infection (carriers), which excrete the bacteria continuously, but without showing symptoms. Carrier animals can eliminate infective B. Hyodysenteriae for 90 days.
2- Vertical transmission.
Which occurs from mother to piglet, although in this case the symptoms are demonstrated in the fattening, when the pigs lose the passive immunity that the mothers give them.
Diagnosis.
The diagnosis of Swine Dysentery depends above all on differentiating it from other potential causes of diarrhea on the farm. Clinical signs such as depression, dehydration and diarrhea with mucus and/or blood. At necropsy the essential finding is enteritis in the large intestine. Mucofibrinous exudate and free blood in the intestinal lumen are characteristic. Definitive confirmation must be made by taking quality samples in the laboratory. Ideal samples should be taken from untreated animals at the beginning of the process and directly from the rectum.
Solutions.
The remedy involves a combination of effective resources, always taking into account the WHO and EU policy of the prudent use of antibiotics in livestock, therefore, antibiotics must remain as a secondary strategy.
The most common alternative measures are:
1) Use of natural additives with antibacterial action that help reduce the pathogenic bacterial population by promoting the growth of beneficial flora.
For this reason, at Biocida ZIX we offer Dysanzix the natural solution that fights the pathogenic bacteria Brachyspira Hyodysenteriae, it also promotes the balance of the microbiota and fights these bacteria without making them resistant. Dysanzix is ??a combination of plant extracts that present complex and synergistic mechanisms of action, guaranteeing its effectiveness and without causing adverse effects on the microbiota of the gastrointestinal tract. The essential oils present in Dysanzix have an effect on the structure of the bacterial cell wall, denaturing the proteins, altering the permeability of the cytoplasmic membrane, causing the interruption of the vital processes of the bacteria and its death.
– Promotes the balance of the intestinal microbiota.
– Regulates the balance of potentially pathogenic bacteria.
– Combination of phytobiotic products. 100% natural.
– Maintains the health of the digestive system.
– Regulates the balance of the microbiome, improving digestive physiology.
– Improves productive parameters.
– Reduces the use of antibiotics.
2) Key biosafety plans in the biocontainment of Swine Dysentery.
- Cleaning and disinfection plan: elimination of organic matter, cleaning with water, use of soaps, rinsing and disinfection. Cleanzix®Foam, Zixvirox®, Virox®.
- Rodent and bird control plan, preventing their access to the warehouses, avoiding the construction of burrows, or eliminating the options to do so. Include anti- bird nets to prevent bird access to internal animals.
- All in – All out, it is very important not to mix batches of animals of different ages and to be able to isolate sick pigs and the pens in which they are located.
3) Use of autovaccines designed from the outbreak, to increase the immunity of the sows so that through colostrum the immunity of the piglet in fattening is improved and colonization is minimized.
4) Design of appropriate nutrition to solve the problem, which is generally based on improving the digestibility of raw materials.
PD eradication plans.
Bringing together the previous solutions, these projects are currently being carried out, given the pathological relevance that DP can have on breeding sows and given that these breeding sows are one of the main sources of dissemination of this disease to their offspring, it has been shown that developing an eradication protocol in productive pyramids (farms of sows that will feed the feedlots or replacement of future breeders) and a good biosafety protocol for all the farms that comprise it, is very useful for the control-eradication of the disease.
These plans have 3 phases:
Phase 1. Farm preparation phase.
– Evaluation of the farm, incidence, severity, risk factors to consider possibilities of success. Brachyspira hyodysenteriae strain isolation and antibiogram.
– Development of the plan adapted to the farm
– Training of the entire team of people who are involved
– Fine-tuning of DDD plans, exhaustive cleaning of all facilities, biosecurity and antiparasitic treatments.
– Partial depopulation of the farm
Phase 2. Treatment or control phase
– Strategic blanket treatment for the entire group of sows (pregnant and lactating) and piglets, with bactericidal doses of the active ingredient best positioned in the antibiogram, for 28 days.
– Cleaning of the animals and transfer to clean places (after 14 days, wash sows and change to a clean place, to prevent reinfections)
– The introduction of animals into new facilities (changes to maternity farms, transitions or fattening, and entry of replacement animals) will always be done following strict biosafety measures, All in All out systems (with adequate cleaning and sanitary gaps) and 28-day preventive medications in the same way.
Phase 3. Follow-up phase and confirmation of success.
– Monitoring and confirmation of eradication, through attempted isolations several months after completing the treatments. Monitoring of improvement of zootechnical performances.
PD is well known to everyone but there is still a long way to go, with all farms vulnerable to its devastating effects. Preventive and corrective measures are our greatest allies. To achieve DP-free farms we must follow the previous recommendations exhaustively, with the use of natural alternatives to antibiotics, biosecurity plans, cleaning and DDD being the keys to success. Any failure in the plan can induce the entry of the disease again.
