Agriculture Business Week

The first part of this series of two articles discussed the nature and diagnosis of the so-called “suis-ide” diseases of pigs caused by Actinobacillus suis, Haemophilus parasuis, and Streptococcus suis. The second part deals with treatment and control of these diseases.

Effective control of the “suis-ide” diseases in a swine herd requires accurate diagnosis and application of proper tools and action steps. As with other infective diseases of pigs, the control of “suis-ide” infections involves three control measures – vaccination, antibiotic medication, and biosecurity.

Although not very much practiced in the Philippines, segregated early weaning (SEW) and off site production have not been very effective in controlling “suis” infections. One reason is that piglets are usually infected at birth from sows. The three “suis” organisms are present in the birth canals of healthy sows, and the majority of piglets may already be colonized at birth and before weaning. Once colonized, these organisms can also be isolated from tonsils and nasal cavities of normal pigs. Horizontal (or pig-to-pig) transmission of infections is therefore most likely to occur when mixing pigs at weaning time, or when maternal immunity has waned.

Vaccination of pigs against the “suis” pathogens may be considered but the degree of protection can be inconsistent. There are a number of commercial vaccines available for H. parasuis and for S. suis, but none for A. suis.

The problem with vaccinating pigs with commercial vaccines for H. parasuis and S. suis is the fact that there are so many strains or known serotypes of these organisms (35 of A. suis and 15 of H. parasuis). With this degree of variation in serotypes, success with commercial vaccines lacks consistency and cross-protection with several other serotypes. The vaccines used in any herd must be the same as the serotypes causing infections in the herd.

This is the reason why the practice of using autogenous vaccines may offer more consistent and more specific protection for the heard. Autogenous vaccines are those that are made from the serotypes that are isolated from the same herd in which it is going to be used.

Another means of “vaccinating” pigs is controlled exposure as a means of controlling disease associated with K parasuis and S. suis. Controlled exposure is done by direct oral administration of inoculum of live H. parasuis and S. suis to five-day-old piglet. This procedure has shown to be a very successful control measure in reducing mortality and morbidity.

Medication with antibiotics is also effective in reducing mortality and morbidity. Early medication is necessary because of the rapid onset of clinical disease. In a farm that practiced judicious use of antibiotics, the sensitivity patterns of the “suis” pathogens were observed to be almost the same across several years. This observation is reassuring the advantages of practicing proper and judicious use of antibiotics.

H. parasuis and A. suis are both Gram-negative organisms which are susceptible to sulfonamides, amoxicillin, and tetracyclines. Tiamulin (e.g. Denagard – Novartis) is generally effective. S. suis is Gram-positive, and sulfonamides, amoxicillin, and lincomycin are typically effective. Injectable penicillin and ceftiofur may be used for individual treatment.

If pigs struggle with “suis” pathogens, a good control measure is to establish a medication regimen during particular phase of the grow-finish period. A chlortetracycline-tiamulin combination in feeds has been proved effective in many cases. In the light of the recent findings about the synergistic or additive effects of tiamulin-amoxicillin combination on some “suis” pathogens, this combination is worth trying.

Managing the ”Suis-ide” Diseases of Pigs Part 1