🦠Pig Diseases - African Swine Fever, Classical Swine Fever, Swine Influenza and Vaccination

Disease management is a critical aspect of swine husbandry. Early identification of symptoms, strict biosecurity measures, and timely vaccination can prevent devastating losses in a pig farming enterprise. Below are the major diseases that affect pigs.

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Viral Diseases

African Swine Fever (ASF)

• It is a highly contagious and fatal viral disease of domestic and wild pigs. ASF is caused by a large DNA virus of the family Asfarviridae, and it is one of the most feared diseases in the global pork industry due to its extremely high mortality rate.

• ASF was detected first in 1921 in Kenya and is generally prevalent and endemic in countries of sub-Saharan Africa, Europe and in some Caribbean countries.
• India notified the first outbreak of ASF virus in January 2020 in the North Eastern States of Assam and Arunachal Pradesh. These states have a high concentration of pig population, making the outbreak particularly devastating for local livelihoods.
• By 2024–25, ASF has spread to 30+ states including UP (Feb 2023), Kerala (Mar 2023), Punjab, Haryana, Rajasthan, Tamil Nadu, Karnataka, Gujarat, and Maharashtra.
• In 2025, Assam alone recorded 300+ epicentres across 30 districts, highlighting the scale of the ongoing crisis.
• African swine fever (ASF) has become a major crisis for the pork industry in recent years.
• The disease can result in up to 100% fatalities in a population. This near-total mortality rate makes ASF one of the most lethal diseases in all of livestock farming.
• It is transmitted through direct and indirect contacts, ingestion of contaminated feedstuffs (including swill/kitchen waste containing infected pork products) and by certain tick vector species. The Ornithodoros tick (soft tick) serves as a biological vector for the virus.

• The disease does not infect humans (not Zoonotic) or other livestock species. This means there is no public health risk from consuming pork from unaffected animals, but the economic impact on pig farmers is catastrophic.
• No commercially approved vaccine globally as of 2025; WOAH adopted a vaccine evaluation standard in May 2025; experimental vaccines exist but biosafety concerns persist. Control = stamping out (culling) + movement restrictions + strict biosecurity + quarantine + proper disposal of carcasses.

• Symptomes:
  • High fever 40-42°C.
  • Loss of appetite.
  • Depression.
  • Lethargic- sometimes refusal to stand or move.
  • Vomiting and/or diarrhoea with bloody discharge.
  • White skinned pigs: extremities (nose, ears, tail and lower legs) become cyanotic (blue-purple colour). Cyanosis is the bluish discolouration of the skin caused by poor blood oxygenation and is a hallmark sign of ASF in white-skinned breeds.
  • Discrete haemorrhages appear in the skin particularly on the ears and flanks.
  • The disease is characterized by sudden deaths in pigs.

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Classical Swine Fever (CSF)

• It is highly contagious viral disease of domestic and wild pigs. Classical Swine Fever (CSF) is caused by a virus of the genus Orthopestivirus in the family Pestiviridae (updated ICTV classification; previously classified under Flaviviridae). CSF virus is an RNA virus — remember this distinguishes it from ASF (DNA virus).
• Also known as hog cholera or pig plague. These older names reflect the severe, cholera-like symptoms that the disease causes in pigs. CSF is considered the most economically important viral disease of pigs globally.

• Young animals more susceptible. Piglets and young pigs have less developed immune systems, making them particularly vulnerable.
• In the acute form of the disease, in all age groups, there is fever, huddling of sick animals, loss of appetite, dullness, weakness, conjunctivitis, constipation followed by diarrhoea, and an unsteady gait.
• Several days after the onset of clinical signs, the ears, abdomen and inner thighs may show a purple discoloration. This characteristic purple discolouration is caused by haemorrhages in the skin (petechiae/ecchymoses) and is one of the most recognizable clinical signs of CSF. High fever of 41–42°C is typically the first sign, followed by neurological signs (circling, convulsions) in the later stages.
• High body temperature, lethargy, yellowish diarrhoea, vomiting, and purple skin discolouration of the ears, lower abdomen, and legs.
• Animals with acute disease die within 1-2 weeks. (High mortality)
• Modified live vaccines (MILV) are used to control CSF. The Lapinized Chinese (LC) strain vaccine is commonly used in India for CSF control. The older Crystal Violet Vaccine (CVV) is also used. Vaccination is the primary tool for prevention since no effective treatment exists.

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Swine Influenza

• Swine influenza is a highly contagious respiratory viral infection of pigs caused by swine influenza virus (Influenza A virus, subtypes H1N1 and H3N2). The virus belongs to the Orthomyxoviridae family and primarily affects the respiratory tract.

• It is characterized by coughing, sneezing, nasal discharge, elevated rectal temperatures, lethargy, difficult breathing, depressed appetite and rarely associated with reproductive disorders such as abortion. While swine influenza is primarily a respiratory disease, it can occasionally cause reproductive problems in pregnant sows. The disease spreads rapidly through a herd but typically has a low mortality rate if secondary bacterial infections are prevented.
• The first clinical signs are fever (40.5-41.5°C), puffy eyes, anorexia leading to loss of weight, depression, prostration and huddling leading to weakness.

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Foot and Mouth Disease (FMD)

• Causative agent: Viral — caused by FMD virus of the genus Aphthovirus.
• Characterized by fever (40-40.6°C).
• Vesicles (blisters) form on the snout, tongue, lips, and feet (between the claws and on the coronary band).
• Affected pigs show lameness, reluctance to move, and excessive salivation.
• FMD is highly contagious and can spread rapidly through a herd.
• Prevention: Vaccination with polyvalent FMD vaccine. Strict quarantine of new animals.

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Swine Pox

• Causative agent: Viral — Swine pox virus.
• Transmitted mainly through the pig louse (Haematopinus suis), which is the main route of swine pox transmission.
• Characterized by round, raised pox lesions on the skin, especially on the belly, inner thighs, and behind the ears.
• Usually self-limiting with low mortality but can be severe in young piglets.
• Prevention: Control of pig lice through regular delousing and maintaining hygiene.

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Porcine Parvo Virus (PPV)

• Porcine parvovirus infection (PPV) is a common and important cause of infectious infertility. PPV is one of the most significant causes of reproductive failure in pigs worldwide.
• Parvovirus affects mainly non-vaccinated primiparous sows, causing reproductive problems such as mummies.
• If pregnant sows become infected with Porcine Parvovirus (PPV) causes reproductive failure. The virus crosses the placental barrier and infects the developing foetuses, leading to death at various stages of gestation.
• An increased numbers of stillbirths. These are associated with the delay in the farrowing mechanism which occurs because of the presence of mummified piglets.
• Small litters associated with embryo loss before 35 days gestation.
• An increase in low birth weight piglets but neonatal deaths are not affected.
• Small mummified piglets in the afterbirth present. The presence of mummified foetuses of varying sizes is a classic indicator of PPV infection, as the virus kills foetuses at different stages of development. Vaccination of gilts before their first breeding is the most effective preventive measure.

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Porcine Circovirosis (PCV2)

• Causative agent: Viral — Porcine Circovirus Type 2 (PCV2).
• Has a huge economic impact on the pig industry worldwide.
• Clinically it presents as a disease which deteriorates animals from weaning to finishing period producing a high mortality rate.
• It also causes dermatitis and nephropathia (kidney disease) with high mortality.
• Vaccination against PCV2 is now widely practised in commercial pig farms.

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Transmissible Gastroenteritis (TGE)

• Causative agent: Viral — Alphacoronavirus (family Coronaviridae) — the TGE virus (TGEV).
• Highly contagious disease causing severe diarrhoea in pigs of all ages.
• Particularly devastating in neonatal piglets with mortality up to 100% in piglets under 2 weeks old.
• Symptoms: Watery diarrhoea, vomiting, dehydration, rapid weight loss.
• Prevention: Biosecurity measures, feedback (controlled exposure of sows to build immunity).

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Porcine Reproductive and Respiratory Syndrome (PRRS)

• Causative agent: Viral — Arterivirus (genus Porartevirus).
• Causes reproductive failure in sows (abortion, stillbirths, mummified foetuses) and respiratory disease in piglets.
• First detected in India: Mizoram, 2013.
• National seroprevalence: approximately 17.8%.
• No cure; vaccination used for prevention in commercial farms.
• Also known as “blue-ear pig disease” due to bluish discolouration of ears in affected pigs. The blue discolouration results from cyanosis caused by respiratory failure reducing blood oxygenation.

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Nipah Virus

• Causative agent: Viral — Paramyxovirus (Nipah virus), genus Henipavirus.
• Pigs are the amplifying host in the bat → pig → human transmission chain.
• First identified in Malaysia (1998–99); pigs were the intermediate host linking fruit bats to human cases.
• India outbreaks: Kerala (2018, 2023, 2026) — primarily bat-to-human, but pig farming proximity is a significant risk factor.
• Zoonotic — bat → pig → human transmission; pig-to-human transmission documented.
• No approved vaccine; supportive treatment only.
• OIE priority pathogen; notifiable disease.
• High case fatality rate (40–75%) in humans.

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Bacterial Diseases

Swine Erysipelas

• Causative agent: Bacteria — Erysipelothrix rhusiopathiae.
• Characterized by high fever and reddish diamond-shaped skin lesions on the body (hence also called diamond skin disease).
• Three clinical forms: (1) Acute — septicaemia, sudden death, high fever; (2) Subacute — characteristic diamond-shaped skin lesions (urticarial plaques); (3) Chronic — arthritis, vegetative endocarditis (heart valve damage), causing poor growth and lameness.
• Acute form can cause sudden death. Chronic form leads to arthritis and heart valve damage (endocarditis).
• Treatment: Penicillin is the drug of choice and is highly effective if given early — Erysipelothrix rhusiopathiae remains penicillin-sensitive.
• Prevention: Vaccination with attenuated or killed bacterin.

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Brucellosis

• Causative agent: Bacteria — Brucella suis.
• Causes reproductive failure in pigs — abortion, stillbirth, and infertility.
• In boars, it causes orchitis (inflammation of testicles) and lameness.
• Zoonotic disease — can infect humans causing undulant fever.
• Prevention: Test and slaughter policy. No effective vaccine for pigs.

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Anthrax

• Causative agent: Bacteria — Bacillus anthracis.
• Peracute form causes sudden death. Acute form shows high fever, swelling of throat, and bloody discharges.
• Zoonotic — dangerous to humans.
• Prevention: Annual vaccination in endemic areas.

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Tuberculosis

• Causative agent: Bacteria — Mycobacterium spp.
• Chronic wasting disease affecting lungs and lymph nodes.
• Prevention: Test and slaughter; maintain clean housing.

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Leptospirosis

• Causative agent: Bacteria — Leptospira spp.
• Causes reproductive failure (abortion, stillbirth, weak piglets), fever, and jaundice.
• Transmitted through contaminated water and urine of infected animals.
• Zoonotic disease — can infect humans.
• Treatment: Antibiotics (streptomycin, tetracycline).
• Prevention: Vaccination, rodent control, drainage of stagnant water.

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Exudative Dermatitis

• Also knonw as Greasy pig. The name “Greasy Pig Disease” comes from the characteristic greasy, oily appearance of the skin in affected piglets.
• The symptoms of this disease are skin lesions caused by an infection of the bacteria Staphlococcus hyicus. The bacteria produces exfoliative toxins that damage the skin, causing it to become red, raw, and covered with a greasy exudate. The disease most commonly affects young piglets between 5 and 35 days of age.

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Swine Dysentery (SD)

• Bacteria Brachyspira hyodysenteriae (B. hydo). This anaerobic spirochaete bacterium colonises the large intestine and causes severe inflammation.
• Infectious disease characterized by mucohemorrhagic diarrhoea and marked inflammation limited to the large intestine. The term mucohemorrhagic means the diarrhoea contains both mucus and blood, which is a hallmark of this disease.

• Soft to watery faeces are common first signs.
• Diarrhoea, usually with mucus and/or blood as signs progress.
• Uneven pig growth, increased mortality, and significantly reduced feed efficiency are seen as disease progresses. The economic impact of swine dysentery extends beyond mortality; the reduced feed efficiency and uneven growth significantly increase the cost of production.

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Parasitic Diseases

Coccidiosis

• This is a protozoan disease. Coccidiosis is caused by single-celled protozoan parasites, not bacteria or viruses.
• This disease is very common in suckling piglets and is caused by intracellular parasite protozoa coccidia. The parasite invades and destroys the intestinal lining cells, disrupting nutrient absorption.
• Diarrhoea, which may become bloody in severe cases, is the primary symptom. The diarrhoea leads to dehydration and weight loss, and severely affected piglets may die. Maintaining clean, dry housing and proper sanitation are key preventive measures.

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Roundworm Infection (Ascariasis)

• Causative agent: Ascaris suum (internal parasite — nematode). Note: A. lumbricoides is the human roundworm; the pig roundworm is A. suum. Ascaris suum is the most common internal parasite of pigs.
• Pigs can be infected with a number of different roundworms. Large roundworms measuring 25-40 cm long can be noticed in the animal’s dung.
• Migrating larvae cause “milk spot” liver (white fibrous spots on liver surface) — a classic post-mortem finding in pigs condemned at slaughter.
• In pigs 2 to 5 months old, the worms cause diarrhoea, weight loss, and lung problems.
• Prevention: Regular deworming, rotational grazing, clean housing.

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Lice Infestation

• Causative agent: Haematopinus suis — the pig louse.
• Causes anaemia in pigs and is the main route of swine pox transmission.
• Control: Regular delousing with approved insecticides, maintaining hygiene.

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Mange (Sarcoptic Mange)

• Causative agent: Sarcoptes scabiei var. suis — an external parasite (mite).
• Characterized by severe itching, swelling, and skin thickening which affects pig growth.
• Treatment: Ivermectin injection or topical acaricides.
• Prevention: Quarantine new animals, regular inspection, clean housing.

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Nutritional Diseases

Piglet Anemia

• Newborn piglets have only limited reserve of iron in the liver for hemoglobin synthesis. Iron is essential for the production of haemoglobin, the protein in red blood cells that carries oxygen to tissues. Without adequate iron, piglets cannot produce enough red blood cells.
• This is due to poor placental transfer of iron to foetus. Unlike many other species, the pig placenta does not efficiently transfer iron from the sow to the developing piglets during pregnancy.
• Also the sow milk is very low in iron, and the suckling pig should be supplemented with iron during the first few days to prevent piglet anemia. Sow’s milk provides only about 1 mg of iron per day, while a rapidly growing piglet requires approximately 7 mg per day.
• Symptom: Pale in the region of ears and belly, rapid breathing and diarrhea. The pallor (paleness) is due to insufficient haemoglobin in the blood, while rapid breathing is the body’s attempt to compensate for reduced oxygen-carrying capacity.
• Control:
  • Placing fresh, clean earth in the piglet’s pen each day. Soil is a natural source of iron and allows piglets to root and ingest small amounts of iron-containing minerals.
  • Daily administration of 4 ml of 1.8% ferrous sulphate solution. Alternatively, an iron dextran injection (200 mg) given intramuscularly within the first 3 days of life is the most common and effective method of iron supplementation in modern pig farming.

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Other Nutritional Deficiency Diseases

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Piglet Mortality

The major task in pig husbandry is avoiding piglet mortality and raising piglets successfully up to 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 iron to the sow.
• Intrapartum death is due to anoxia induced by lack of placental blood flow associated with uterine contraction or premature rupture of umbilical cord. This occurs mostly in aged sows.
• The pre-weaning mortality ranges between 12-30%.

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Complete Disease Summary Table

Disease	Type	Causative Agent	Key Feature
African Swine Fever	Viral	Asfivirus (Asfarviridae)	100% fatality, no approved vaccine (2025)
Classical Swine Fever	Viral	Orthopestivirus (Pestiviridae)	Purple discolouration, MILV vaccine
Swine Influenza	Viral	Orthomyxovirus	Respiratory, low mortality
Foot and Mouth Disease	Viral	Aphthovirus	Vesicles on snout/feet, fever
Swine Pox	Viral	Swine pox virus	Pox lesions, spread by lice
Porcine Parvo Virus	Viral	Parvovirus	Reproductive failure, mummified foetuses
Porcine Circovirosis	Viral	PCV2	Wasting, dermatitis, nephropathia
TGE	Viral	Alphacoronavirus (Coronaviridae)	Severe diarrhoea, 100% mortality in neonates
PRRS	Viral	Arterivirus (Porartevirus)	Reproductive failure + respiratory; India: Mizoram 2013
Nipah Virus	Viral (Zoonotic)	Paramyxovirus (Henipavirus)	Pigs = amplifying host; bat→pig→human; Kerala outbreaks
Swine Erysipelas	Bacterial	E. rhusiopathiae	Diamond-shaped red skin lesions; 3 forms: acute/subacute/chronic; zoonotic (erysipeloid); treatment: Penicillin
Brucellosis	Bacterial	Brucella suis	Abortion, zoonotic
Anthrax	Bacterial	Bacillus anthracis	Sudden death, zoonotic
Leptospirosis	Bacterial	Leptospira spp.	Abortion, jaundice, zoonotic
Exudative Dermatitis	Bacterial	S. hyicus	Greasy skin, 5-35 days age
Swine Dysentery	Bacterial	B. hyodysenteriae	Mucohemorrhagic diarrhoea
Coccidiosis	Protozoan	Coccidia	Diarrhoea in suckling piglets
Ascariasis	Parasitic	Ascaris suum	25-40 cm worms; most common internal parasite; milk spot liver
Trichinellosis	Parasitic (Zoonotic)	Trichinella spiralis	Encysted larvae in muscle; humans infected via undercooked pork
Mange	Parasitic	Sarcoptes scabiei	Severe itching, skin thickening
Piglet Anemia	Nutritional	Iron deficiency	Pallor, rapid breathing
Parakeratosis	Nutritional	Zinc deficiency	Crusty skin lesions
Mulberry Heart	Nutritional	Vit E / Selenium deficiency	Sudden death

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Common Disinfectants and Their Usage

Disinfection means destruction of pathogenic microorganisms from a place so that it becomes free from infection. A disinfectant, germicide, or antiseptic is a substance able to kill organisms and their spores at appropriate concentrations.

References & Sources

1

G.C. Banerjee: A Textbook of Animal HusbandryBook

2

Wikipedia — Animal HusbandryWeb

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Summary Cheat Sheet