Disease Management

Healthy pigs are very important for performance of pig and success of a pig farm. A pig farm can be affected with certain diseases causing loss to the pig owners. Sick pigs generally have the following signs:

• It may not eat or not show interest in feed/water
• It may breath rapidly indication of a fever
• In white skin-colored pigs the skin may become reddish
• It may have diarrhea which may sometimes be bloody or blood stained
• Droopy ears or ears pointing downwards
• Dull eyes
• Dull skin and hair
• Its tail will become limp
• Separates itself from the rest

Bacterial diseases

1. Swine Eryseplas

• Erysipelas in swine is caused primarily by Erysipelothrix rhusiopathiae, a bacteria carried by up to 50% of pigs.

Symptoms

• Erysipelas occurs in pigs of all ages, but pigs from 2 months to one year age are highly susceptible.

Acute

• The acute disease is characterized by high fever, in appetence, depression, a rapid course of illness, and death within 2-3 days in untreated animals.
• Light pink to light purple lesions are indicative of a non-fatal, whereas grey, dark purplish and red lesions usually proceeds death.
• Some animals may show a stiff gait and reluctance to stand or move, and urticarial cutaneous lesions may develop.
• The diamond shaped raised skin lesions are pathognomonic. Pregnant sows may abort.

Chronic

• In the chronic form arthritis is more common.
• The hock, stifle, elbow and carpal joints are most likely to be affected resulting in severe lameness. The mitral valves are involved in valvular endocarditis. Diamond shaped skin lesions are pathognomonic.

Diagnosis can be achieved by

• Based on symptom and lesions
• Gram-positive rods in acute cases and Gram-positive filaments in chronic cases.

Treatment

• In addition to hyper immune serum, treatment with antibiotics such as penicillin and tetracyclines are effective.
• Vaccination is recommended twice a year.

2. Brucellosis

• Swine brucellosis is a zoonotic disease. Those working with feral swine and in abattoirs should take necessary precautions to prevent exposure.
• Serologic testing is necessary for identifying infected swine.
• Testing and removal of seropositive swine is the foundation of the control program.

Symptoms

• After exposure to Brucella suis, pigs develop a bacteremia that may persist for up to 90 days and continue shedding for upto 3 years. During and after the bacteremia, localization typically occurs in lymphatics, spleen, liver, and mammary and reproductive tissues.
• Clinical signs depend considerably on the site(s) of bacterial colonization and commonly includes abortion, temporary or permanent sterility, orchitis, lameness, hindlimb paralysis, spondylitis, metritis and abscess formation (occasionally).
• The incidence of abortion may range from 0% to 80%. Abortions may also occur early in gestation and be undetected. Usually, sows or gilts that abort early in gestation return to estrus soon afterward and are rebred.
• Infection early in pregnancy commonly results in reproductive failure, including decreased litter size, abortion, stillbirth, and birth of weak piglets.
• Infertility in sows, gilts, and boars is common and may be the only clinical sign of brucellosis. Before attempting treatment for other diseases, it is logical to test for brucellosis in herds in which sterility is a problem.
• Infertility in sows is usually temporary but may be permanent. In boars, orchitis, usually unilateral, may occur, and fertility appears to decrease.

Diagnosis

• The principal means of diagnosis in pigs is serologic testing, such as the brucellosis card (rose bengal) test, other serum agglutination tests, or complement fixation tests. These tests are used in series to confirm seropositivity.
• It is generally accepted that the tests have limitations in detecting brucellosis in individual pigs. Thus, entire herds or units of herds, rather than individual pigs, must be tested in any control program.
• Low agglutinin titers occur in almost any size herd, regardless of infection status, and few infected pigs may have no detectable titer.

Prevention and control

• Replacement swine should be purchased from herds known to be free of brucellosis, or they should be tested, isolated for 3 months, and retested before being added to the herd.
• Pigs should be isolated on return from fairs or shows before reentering the herd. Domestic pigs should be kept in a manner to prevent interactions with feral swine.
• There is no vaccine for brucellosis in swine, and no practical recommendations can be made for treatment.
• Control is based on test and removal of infected breeding animals. Brucellosis remains a problem in feral swine and is a potential source of infection for domesticated herds and for humans.
• Depopulating the infected herd to eradicate the disease.

3. Leptospirosis

• Like most other mammals, pigs are susceptible to infection by numerous serovars/genomospecies of leptospires. The importance of leptospirosis as a clinical disease of swine and an occupational risk to swine industry workers, is highly variable across countries and can wax and wane.
• Swine are maintenance hosts (ie, they act as a source of infection for their own species) and infections are subclinical in non-pregnant animals.
• Serovar Pomona has been of greatest importance with respect to reproductive disease in pigs and to zoonotic risk.
• Abortions occurring 2–4 weeks before term are the most common manifestation of leptospirosis in pigs. Piglets produced at term may be dead or weak and may die soon after birth. Inappetance, fever, diarrhea lasting for 1-3 days, abortion during last 3 weeks of expected gestation
• The principal differential diagnosis is porcine reproductive and respiratory syndrome. Other infectious causes of pregnancy loss include brucellosis, parvovirus, and porcine circovirus.
• Treatment and control of leptospirosis may include a combination of vaccination, medication, and management changes.
• Immunization with bacterins is widely practiced in breeding herds and reduces the prevalence of infection and abortions.
• Bacterins should not be expected to eliminate renal infection. Immunity is serovar specific, and vaccines should include all serovars known to be clinically important in a region.

4. Atrophic rhinitis

• Atrophic rhinitis is characterized by sneezing, followed by atrophy of the turbinate bones, which may be accompanied by distortion of the nasal septum and shortening or twisting of the upper jaw. Its significance has declined substantially, and it is no longer considered a major health risk to swine herds.
• Atrophic rhinitis has been divided into two forms: non-progressive atrophic rhinitis, due to B bronchiseptica, is mild and transient and generally has little effect on growth and performance.
• Progressive atrophic rhinitis, due to toxigenic P multocida, is severe, permanent, and usually accompanied by poor growth.
• Outbreaks of disease usually follow either the introduction of infected pigs or mixing of pigs from different sources.
• Acute signs of atrophic rhinitis, which usually appear at 3–8 weeks of age, include sneezing, coughing, and inflammation of the lacrimal duct. In more severe cases, nasal hemorrhage may occur.
• The severity of atrophic rhinitis in a herd depends largely on the presence of toxigenic strains of P multocida, management practices, and the immune status of the herd.
• The signs and lesions are commonly the basis for diagnosis of atrophic rhinitis; however, the presence of toxigenic strains of P multocida should be confirmed. Routine monitoring is done in some breeding herds by measuring the degree of turbinate atrophy and giving the herd an atrophy score.
• Due to elimination programs of toxigenic P multocida at the seedstock level, atrophic rhinitis is rarely observed in modern swine production systems.
• Sows are vaccinated 4 and 2 weeks before farrowing, and the young pigs at 1 and 4 weeks of age. A high level of colostral immunity is acquired by piglets nursing vaccinated sows.
• The recovery may not prevent the stock from acting as carriers of infection.

5. Salmonellosis

• Salmonella enterica is one of the most common Salmonella species affecting pigs. It sometimes produces necrotizing enterocolitis; more commonly, it is associated with septicemic disease characterized by hepatitis and pneumonia. Intestinal salmonellosis in pigs has traditionally been associated with either S Choleraesuis or S Typhimurium.
• Sources of infection with these serotypes are primarily asymptomatic carrier pigs; however, rodents and contaminated feed and premises may also be sources.
• Intestinal salmonellosis is most often observed in pigs from weaning upto about 5 months old; however, it can occur at other ages. Affected pigs are commonly febrile, with reduced feed intake, and have liquid yellow feces that may contain shreds of necrotic debris.
• Restless and febrile (40.6o-41.7oC), diarrhea is seen on third to fourth day with watery yellow feces, mortality is high.
• Culture of feces or intestinal mucosa using selective media, with or without enrichment, is useful to isolate salmonellae from clinical samples and can be completed in a few days.
• Culture is typically followed by serotyping to confirm the serotype involved. PCR assays are increasingly available, often with serotype-level specificity that can reduce the time to final etiologic diagnosis.
• Histological examination of affected intestine and liver tissue to differentiate intestinal salmonellosis from proliferative enteropathy and swine dysentery is of high diagnostic value.
• Parenteral administration of antimicrobials to acutely ill pigs and medication of the affected group via water or feed may decrease the severity of an outbreak of intestinal salmonellosis.

6. Pasteurellosis

• Pasteurellosis is most commonly seen in pigs as a complication of mycoplasmal pneumonia, although swine influenza, Aujeszky disease, Bordetella bronchiseptica, or Haemophilus parahaemolyticus may also cause changes in the lungs that lead to disease caused by Pasteurella spp.
• The causative organism usually is P multocida.
• Primary, sporadic, fibrinous pneumonia due to pasteurellae, with no epidemiologic connection with mycoplasmal or other pneumonia, may also be seen in pigs. In both primary and secondary forms, chronic thoracic lesions and polyarthritis tend to develop
• Sudden onset, weakness, incoordinated gait, high temperature (105-106F), coughs, dyspnea, anorexia and labored “thumpy abdominal breathing.
• Diagnosis of pasteurellosis is based on necropsy findings and recovery of pasteurellae from the lesions. Non-toxigenic strains of capsular type A are the predominant isolates from cases of pneumonia.
• Septicemic pasteurellosis and meningitis occasionally occur in piglets. Mannheimia haemolytica has been recovered from aborted fetuses, and septicemia may also occur in adult pigs.
• There are no distinctive lesions, and the pathogenesis is obscure. Porcine strains of M haemolytica are often untypeable and do not belong to the common ovine and bovine serotypes.
• Control of the secondary, pneumonic form of pasteurellosis is generally based on prevention or control of mycoplasmal pneumonia. Early and vigorous therapy with antibiotics, or in combination with sulfonamides, is indicated to prevent chronic sequelae of all forms of the disease.
• An increasing resistance to some antibiotics has been noted among the pasteurellae.
• Vaccination is recommended

7. Clostridial enteritis

• Infection of the small intestine by type C strains of Clostridium perfringens causes highly fatal, necrohemorrhagic enteritis. It most commonly affects piglets of 1–5 days old; however, in rare cases it occurs in pigs up to 21 days old and other species.
• Entire litters are typically affected, and mortality is close to 100%. In less severe cases, brownish liquid feces develop at 3–5 days. Infrequently, pigs develop a persistent, pasty-gray diarrhea and become progressively emaciated.
• Diagnosis is based on clinical signs and lesions in suckling pigs and also by detection of beta toxin in feces, or via culture and genotyping.
• Diagnosis is via a combination of lesion assessment and bacterial isolation and typing.
• Immunization is recommended along with good sanitation management.
• Treatment is of little value after clinical signs occur. Further, increasing lactogenic immunity on sow farms is essential for control.

Viral diseases

1. Foot and Mouth Disease

• Viral disease of pigs caused by FMD virus of the genus Aphtho virus.
• Characterized by fever (40-40.6ºC), anorexia, reluctance to move, and scream when forced to move.
• These signs are followed by vesicles on the coronary band, heals, inter digital space and on the snout.
• Mouth lesions are not too common and when they occur are smaller and of shorter duration than in cattle and tend to be a "dry"-type lesion.
• There is no drooling. Sows may abort. Piglets may die without showing any clinical sign.

Clinical Signs

• Pyrexia, though this clinical sign is inconsistent
• Severe foot lesions and lameness, with detachment of the claw horn, especially when housed on concrete
• Vesicles on pressure points of limbs, especially along the carpus, resulting in knuckling
• Vesicular lesions on the snout
• Abortion.
• Prevention of movement of animals and animal products in the area affected.
• Disinfect vehicles leaving the infected area.

Diagnosis

• Based on symptom and lesions

2. Swine Influenza

• Swine influenza is a highly contagious respiratory viral infection of pigs caused by swine influenza virus, characterized by coughing, sneezing, nasal discharge, elevated rectal temperatures, lethargy, difficult breathing, depressed appetite and rarely associated with reproductive disorders such as abortion.
• The first clinical signs are fever (40.5-41.5ºC), puffy eyes, anorexia leading to loss of weight, depression, prostration and huddling leading to weakness. These signs are followed by sudden onset of acute respiratory signs, which include paroxysmal coughing, sneezing, irregular abdominal breathing and ocular and nasal discharges.
• Swine influenza is caused by influenza A viruses, which are further characterised by subtypes. The most common subtypes are H1N1, H1N2 and H3N2.
• In breeding stock, abortions, infertility, production of small weak litters and increased stillbirths.
• Swine influenza viruses are found mainly in pigs, but they have also been found in other species including humans, turkeys, and ducks. Infected pigs may begin excreting swine influenza viruses within 24 hours of infection, and typically shed the viruses for 7-10 days.

Clinical Signs

• The clinical signs usually appear within 1 to 3 days in pigs, and most animals recover within 3-7 days if there are no secondary infections or other complications.
• Swine influenza is an acute upper respiratory disease characterized by fever, lethargy, anorexia, weight loss, and laboured breathing. Coughing, sneezing, and nasal discharge are commonly seen.
• Conjunctivitis is a less common clinical sign. Abortions may also occur. Some strains can circulate in pigs with few or no clinical signs.
• Complications may include secondary bacterial or other viral infections. Severe, secondary potentially fatal bronchopneumonia is occasionally seen.

Diagnosis

• Swine influenza may be suspected on the basis of clinical signs and events leading to the disease, but is only one of the pathogens that commonly cause respiratory disease in pigs.
• Laboratory tests are required to confirm the diagnosis.

Prevention and Control

• Good biosecurity measures are important to prevent transmission through fomites and mechanical vectors.
• Once a swine herd has been infected, the virus can persist in the herd and cause periodic outbreaks; however, good management can decrease the frequency, extent of outbreaks and severity of disease.
• Once swine influenza is established on a farm, it is very difficult to completely clear and the depopulation of herds may be necessary.
• People ill with influenza viruses have reportedly infected pigs; while this is possible, these events are not well documented.
• People working with pigs should follow the same advice as provided to the general public and stay home if showing flu-like symptoms.
• Inactivated influenza vaccines are also available for some influenza virus infections in pigs.
• To provide adequate protection, influenza vaccines need to reflect the current subtypes and strains in a geographic area and may need change periodically.
• These vaccines do not always prevent infection or virus shedding, but appropriately vaccinated pigs generally have milder disease if they are infected.
• Good husbandry practices including All-in/All-out to limit the spread of the disease, provision of fresh clean drinking water, avoiding ducks and turkey contamination's/contact including staff and proper use of disinfectants to clean infected buildings.

3. Classical swine fever

• Classical swine fever (CSF) is a contagious viral disease of pigs. CSF is caused by a virus belonging to the family Flaviviridae and the genus pestivirus.
• Classical swine fever (CSF), also known as hog cholera, is a contagious viral disease of domestic and wild swine. It is caused by a virus of the genus Pestivirus of the family Flaviviridae, which is closely related to the viruses that cause bovine viral diarrhoea in cattle and border disease in sheep.
• There is only one serotype of CSF virus (CSFV). CSF is a disease listed by the World Organization for Animal Health (WOAH) Terrestrial Animal Health Code and must be reported to the WOAH (WOAH Terrestrial Animal Health Code).

Symptoms

• Acute infection: In acute form, the pigs appear sick, inactive and drowsy with arched back. Some pigs stand with droopy head and straight tail. Huddling, vomiting, high fever anorexia and constipation. Conjunctivitis, staggering gait, posterior weakness and purple discoloration of abdominal skin
• In last stage of the infection, pigs will become recumbent, and convulsions may occur shortly before death. Sever diarrhoea will also occur during last stages.
• Chronic form: Dullness, capricious appetite, pyrexia and diarrhoea for up to 1 month. Weight loss, hair loss, dermatitis and discoloration of abdomen or ears are the other symptoms. A chronically infected pig may have a disproportionately large head relative to the small trunk.

Diagnosis

• Based on high morbidity and mortality, high fever, diarrhoea. Kidney and lymph node lesions will help in field diagnosis.
• Because the clinical signs are not exclusive to CSF, and vary widely, laboratory tests are required to detect antibodies or the virus itself.

Prevention and Control

• Treatment is not attempted. Affected pigs must be slaughtered and the carcasses buried or incinerated.
• The first barrier to prevent an outbreak of CSF is to apply strict and rigorous sanitary prophylaxis, as defined in the WOAH.
• Modified live vaccines (MLV) are used to control CSF.
• The udder and teat of sow should be dry and kept hygiene to avoid such problem

When an outbreak occurs, many actions must be set in place urgently:

• Slaughter of all pigs on affected farms
• Safe disposal of carcasses, bedding, etc.
• Thorough disinfection
• Designation of infected zone, with control of pig movements
• Detailed epidemiological investigation, with tracing of possible sources (up-stream) and
• Surveillance of infected zone, and surrounding area

In areas where the disease is endemic, vaccination can prevent the spread of the disease. In disease-free areas, a stamping out policy is applied consisting of early detection, movement control, proper disposal of carcasses, and cleaning and disinfection.

3. Swine pox

• Swinepox is an acute, often mild, infectious disease characterized by skin eruptions that affects only pigs.
• Swinepox virus is distinct from other poxviruses and does not protect against infection with vaccinia virus. It will grow on pig cell cultures, but not embryonating eggs. It is relatively heat stable and survives for ~10 days at 37°C (98.6°F).
• The disease is most frequently seen in young pigs, 3–6 weeks old, but all ages may be affected. After an incubation period of ~1 week, small red areas may be seen most frequently on the face, ears, inside the legs, and abdomen. These develop into papules and, within a few days, pustules or small vesicles may be seen.
• The centers of the pustules become dry and scabbed and are surrounded by a raised, inflamed zone so that the lesions appear umbilicated. Later, dark scabs (1–2 cm in diameter) form, giving affected piglets a spotted appearance.
• The early stage of the disease may be accompanied by mild fever, inappetence, and dullness. Few pigs die of uncomplicated swinepox.
• Virus is abundant in the lesions and can be transferred from pig to pig by the biting louse (Haematopinus suis). The disease also may be transmitted, possibly between farms, by other insects acting as mechanical carriers.
• Recovered pigs are immune. There is no specific treatment. Eradication of lice is important.
• Improve sanitation, newly purchased pigs may be examined for lesions.

Piglet Mortality

• The major task in pig husbandry is avoiding piglet mortality and raising piglets successfully upto weaning.
• After weaning the mortality is comparatively less Pre-partum death may be due to deficiency of iron, which can be prevented by injection of sow with iron. Intrapartum death is due to anoxia induced by lack of placental blood flow associated with uterine contraction or premature rupture of umbilical card. This intra-partum death occurs mostly in aged sows.
• Pre-weaning mortality: The pre-weaning mortality ranges between 12-30%.

Causes of mortality

Starvation and overlying by the pig

70% of death is due to starvation and overlying by the sow, which can be avoided by

1. Improving birth weight and vigor of newborn piglets
2. Minimizing risk of chilling or hypothermia
3. Minimizing agalactia

It is a part of complex condition of MMA (M= mastitis, M= metritis & A=agalactia). The MMA syndrome can involve metabolic, bacterial and hormonal factor with stress plays a part. Since its main effect is loss of milk in the first three days after farrowing, the condition contributes to piglet loss from starvation.

Reason and control of MMA

• Elevated temperature of sow is associated with this condition, hence regular monitoring of sows rectal temperature and treatment with antibiotic and oxytocin is essential to avoid this condition.
• Such conditions which are not detected earlier, it can be noticed by loss of body condition of piglets and it is very difficult to recover the condition quickly.
• In refractory case, prompt provision of an alternative source of food for piglet by foster sow or artificial feeding will minimize the loss.

Piglet anemia

The newborn piglet has only limited reserve of iron in the liver for hemoglobin synthesis. This is due to poor placental transfer of iron to fetus. The sow milk is very low in iron and the suckling pig should be supplemented with iron during first few days to prevent piglet anaemia.

Symptoms

• Pale in the region of ears and belly
• Listlessness
• Rapid breathing
• Often exhibit diarrhea

Control

• Placing fresh, clean earth in the piglets pen each day
• Using soil drenched with a solution made from 500 gm ferrous sulphate, 75 gm copper sulphate and 3 litrees of water
• Daily administration of 4 ml of 1.8 percent ferrous sulphate solution
• The daily painting of the mother’s udder with ferrous sulphate solution and sugar [0.5 kg of ferrous sulphate in 10 liter of water].
• All these methods are labour intensive and the safest and easiest method of combating piglet anemia is to inject the piglet with 100-150 mg of iron in the form of iron dextron 3 days after birth.
• If necessary, a second and slightly smaller injection can be made some 3 weeks later.

Vaccination Schedule for Pigs

External parasitic infestations

External parasites mainly include mange, lies and myiasis.

Mange

It is caused by small parasites called mites that live in the skin. They provoke severe itching and irritation. Nowadays sarcoptic mange in pigs has been reported in all major swine producing countries and is most prevalent in Brazilian swine herds. Lesions, or scabs, on the animals may start on any part of the body, but usually appear first on the head, around the eyes, nose, or ears; lesions may progress to hyperkeratosis and exfoliation of epidermal debris.

Lice

These are blood suckers that also cause irritation of the skin. The hog louse is the largest louse species commonly associated with domestic animals. It is found that most frequently in the folds of skin behind the ears and between the legs. The blood-sucking activity of hog lice results in much irritation and discomfort to swine.

Myiasis

Disease caused by flies, which lay eggs in the wounds. The eggs hatch into larvae which live and feed on the flesh and developed into pupate, and fall off when they mature, creating more wounds.

Control of Lice, Flies, Mange

1. Scrub sows with Gamma BHC insecticides four days before farrowing.
2. Clean and scrub the farrowing pens before use.
3. Maintain proper animal nutrition and health program to reduce severity and spread.
4. Use recommended control products as advised by veterinarian

Internal parasites of pigs

Worms are one of the most serious threats to pig keeping. There are more than 30 types affecting the intestines of pigs. The most important two are the intestinal round worm and the tapeworm.

Roundworm:

Round worms live in the gut and take food from the pig. The pig can therefore become thin. Giant intestinal roundworms (Ascaris lumbricoides) are common around the world, especially in warm, moist climates. These worms are large, about the size of a pencil. The infection begins with the ingestion of eggs which are usually present in contaminated soil,or on fruits and vegetables grown in infected soil.

Tapeworm

Tapeworms are flat and long ribbon like creatures which are common in all parts of the world. Tapeworms do not have a digestive system so they receive their food through their skin as they absorb our nutrients. They especially absorb folic acid and vitamin B-12. These parasites may cause what is referred to as “verminous intoxication” as they put out and leave dangerous waste products in our bodies.

These tapeworms can roll themselves into a ball and can be felt on the right side of the abdomen under the liver. Pork measles is caused by tapeworms which live in the muscles of pigs. They do not usually affect the pig, but can lead to pain and the pig may find it difficult to move around. When people eat under cooked measly pork, the worms develop inside the people, and can make them very sick.

Deworming

Ivermectin, Fenbendazole, Levamisole, Pyrantel, Dichlorvos and Piperazine are frequently used, effective and safe dewormers. The deworming schedule should include pre-breeding for all breeding stock and pre-farrowing for gilts and sows, prevention of Strongyloides and roundworms in baby pigs, and one or more dewormings in weanling and growing pigs. Specific strategic schedules should be arranged with the help of veterinarian.

• Boars- every 6 months
• Sows- 2 weeks before farrowing and after weaning
• Piglets-1 week after weaning
• Fatteners-1week after weaning and 3 months later
• Gilts-1week after weaning, 3months and at 7 months of age at least 2 weeks before service