The Swine Fevers


Other names

Swine Fever  - Hog Cholera, CSF, Swine Fever

African Swine Fever -  ASF

Causal agent

Classical Swine Fever - Virus - a Flaviviridae, genus Pestivirus.  Enveloped RNA virus

African Swine Fever - Virus -   Enveloped DNA virus related to Poxviruses

Age group

Any age group of pig can be infected with CSF or ASF

Clinical signs


It is not possible clinically to distinguish between CSF and ASF

Naive herds

Swine fever 3

Piglet with multiple haemorrhages over the skin

Initially a few pigs appear drowsy and less active, with some anorexia and they may appear chilled

Within days, pigs will present with a marked fever (41-42•C), sometimes with a reddening of the skin

The pigs develop a conjunctivitis and constipation leading to yellowish diarrhoea

The pigs appear chilled and will huddle together

A few pigs may convulse before they die

Pigs start to die with a spreading purple discoloration of the skin. Death often occurs some 10 to 20 days post-infection

Pigs which survive will be chronically affected with severe retardation of growth and often present with arched backs

In the adult herd, returns, abortions, and an increase in mummified and stillborn piglets

On established herds

Congenital infection

Piglets infected from their mothers during pregnancy can result in abortion, mummification, malformations (may present with a congenital tremor with cerebral hypoplasia with Classical Swine Fever), stillbirths and weak born piglets.  Piglets born from CSF infected mothers may remain healthy but continually spread the disease through out their lives

Rest of the herd

An almost in apparent infection can also be present on chronically infected herd.  These herds can be very difficult to identify



Your vet and the  government vets must be informed of any suspicious clinical signs

If you are suspicious samples should not be taken, discuss with the government.

In positive countries, samples can be obtained from tonsilar swabs using Dacron swabs






Prevent any pork products entering the farm and being fed to the pigs

Prevent any infected pigs entering the farm

All pigs from infected herds are slaughtered and destroyed and the farm intensely disinfected

In ASF areas, control ticks and flies that may transmit the disease

In endemic parts of the world vaccines are available

Common differentials


PDNS, Salmonellosis, Acute pasteurellosis, Erysipelas, Acute septicaemic streptococcal infections, PDNS, Thrombocytopaenia, Warfarin poisoning. Haemophilus parasuis.  Reproductive diseases. Other causes of congenital tremor.




The virus is able to survive in uncooked and cured pork and pork products for months

The introduction of new animals or pork products from infected herds, into a herd is the most likely source of infection

The diseases can be carried on boots, vehicles, clothing, and also pets and birds

The diseases can be carried by wild boar

Classical Swine


The virus is quite resistant in the environment, surviving a couple of days

The virus is quite readily inactivated by approved disinfectants

Other members of the Pestivirus genus can cause disease in pigs, notably Bovine Viral Diarrhoea and Border’s Disease.

The virus is excreted from pigs for 10-20 days post-infection in large amounts

African Swine


The virus is very resistant in the environment, surviving for months

The disease can be spread by ticks (Ornithodoros species in Africa)

Recovered animals remain infective for at least 6 months

The virus is inactivated by approved disinfectants

Post-mortem Lesions


The pigs may die so rapidly that there are few post-mortem signs


Multiple haemorrhages through out the carcase

Swollen, oedematous  and haemorrhagic lymph nodes

Infarction of the spleen (large areas where the blood supply has been cut off resulting in blood filled blebs on the surface of the spleen)


In CSF ulceration (button ulcers) can be seen in the large intestine

swine fever k3 button ulcer

Swine Fever bladder 2

Button ulcers in the large intestine

Haemorrhages in the bladder

Haemorrhages on the epiglottis and larynx

swine fever k14 spleen infarct

Swine fever kr 66 kidney


Splenic infarcts

Petechial haemorhages kidney


Note the feeding of waste feed, including household scraps, unless it is cooked in a plant operating under a licence is prohibited in many countries. 

Several countries have now banned the feeding of any waste feed containing mammalian meat proteins