A comparison between African Swine Fever and Classical swine fever

 

African swine fever (ASF) and classical swine fever (CSF) are highly contagious viral diseases of pigs. They are clinically similar, and cannot be definitively distinguished from each other in the field. Laboratory testing is required to confirm a diagnosis. 

Although both disease have similar clinical symptoms, but ASF have higher mortality rate which reach 100% than CSF. Respiratory lesion is common in ASF but not CSF.

Below is a comparison table between ASF and CSF. 

	Classical Swine Fever	African Swune Fever
	Highly contagious, rapid spread, endemic in most Asian countries due large herd size	All age affected (include finisher, sow)
Agent	Flaviviridae(lipid envelop RNA virus, stable in adverse condition)	Asfarviridae, large, icosahedral, linear double-stranded DNA virus 2 genotype
Reason for outbreak	Introduction of new pig, vaccination programme lapse, change in vaccine programme, Swill feeding, mechanical mean	Tick transmission( Europe country), wild pigs( warthogs) Swill meal,mechanical transmission (Asian country)
CS	Acute(highly virulent strain)=sudden onset, short period 10-20day(pyrexia 40-41C, depression, anorexia, convulsion, hemorrhage, nervous sign( non suppurative encephalitis Conjunctivitis,constipation, chilled, shiver Subacute(low virulent strain)=1-3 mth, depress, fever, recover, emaciation, stunted growth, secondary bacteria pneumonia Profuse watery yellowish diarrhea Chronic=wasting syndrome, ill, depress, stunted growth, some resemble skin dermatitis, no hemorrhage evidences	Acute resembles CSF, erysipelas Incubation period= 4-19 days CS depend on virulence, exposure dose, infection route   Highly virulent isolates(90-100% mortality)= peracute, acute forms Acute: 4-7 day IP, increase resp rate, high fever 40-42% Moderaly virulent isolates(20-40%)=acute, subacute, chronic, inapparent Subacute- 7-14 days PI, labored respiration, fever, hemorrhage, mild joint swelling Low virulent isolates(10-30%)= subacute, chronic, inapparent Chronic: coughing, intermittent, low fever, reddened, raised skin,
PM	Acute CSF=Red patch skin hemorrhage, purplish discoloration of skin Chronic CSF=button ulcers(complicated with Salmonellosis)	Acute=cyanosis, hemorrhage Subacute-more pronounced hemorrhage Chronic= reddened, raised, necrotic skin areas
Diagnoses     Sample: tonsils	Lab confirmation for chronic, subacute CSF, Direct immunofluorescent test on organ sections(virus isolation, detection of viral antigen), ELISA Gold standard-Virus isolation+ immunofluorescence staining Others: ELISA(widely use), PCR	Lab test, samples (lymph node, spleen, kidney, lung, blood serum, oral fluid) 1.Antigen=PCR( VP72 genome), IFAT, Hemodsorption test ELISA- screening, 2. Antibody demonstration= ELISA test, IFAT
Control and Prevention	COMPULSORY Vaccine Live attenuated vaccine in endemic country (Sow and litter at weaning 4 week, revaccinate at 7/8 weeks of age) Subunit vaccine less use no ideal protective levels	No effective tx  or vaccine Restrict pig movement Country with ASF contingency plan Biosecurity can prevent ASF