Pathogenesis of Hepatocellular Disease

Study Notes

Epidemic occurs in rainfalls, with floods, liver damage, and hepatocellular necrosis
Transmission occurs through contact with infected animals or humans, including blood, body fluids, eye, and organs
Incubation period is 2-6 days, with outcomes ranging from symptomatic to asymptomatic
Complications include meningoencephalitis, ocular disease, haemorrhagic fever, and hepatitis

Group of severe illnesses caused by four groups of RNA viruses (Filoviridae, Arenaviridae, Bunyaviridae, and Flaviviridae)
Most VHF infections occur in outbreaks, with severity and ability to spread widely among populations
VHF can be used as biological weapons (bioterrorism)

Genus Filovirus: Ebola and Marburg
Structure: filamentous, pleomorphic, enveloped, helical nucleocapsid, linear single-stranded RNA (-ve sense)
Ebola: first identified in 1976 in Zaire (DRC), with mortality rates up to 90%
Ebola has 5 subtypes: Zaire, Sudan, Cot’ivoir, Bundibugyo, and Reston

Pathogenesis: classical VHF plus extensive widespread necrosis in liver, spleen, kidneys, heart, and lymph nodes
Clinical features: incubation period 2-21 days, prodrome phase, bleeding stage, and late stage
Diagnosis: complete blood count, liver function test, virology, serology, molecular, and immunohistochemistry
Management: antiviral therapy under trials, supportive therapy, and maintenance of fluid and electrolytes balance
Prevention: vaccine under trials, isolation of cases, health staff precautions, and proper environmental decontamination

Most common arboviral infection in humans, with highest prevalence in Southeast Asia
Risk factors: age, gender, preexisting antibodies, and genetic factors
Transmission: Aedes aegypti, early morning and late afternoon feeder
Pathogenesis: marked vascular permeability, shock, and hepatic involvement
Clinical features: incubation period 3-14 days, 4 syndromes (undifferentiated fever, classical dengue fever, dengue haemorrhagic fever, and dengue shock syndrome)
Diagnosis: haematological, virological, and serology
Management: supportive treatment, vaccine under research, and mosquito control

An arboviral infection ranging from acute febrile illness to life-threatening viral haemorrhagic fever
Largest prevalence in Africa and South America
Transmission: mosquitoes (Aedes and Haemogogus)
Clinical features: incubation period 3-6 days, mild disease, and severe (malignant) disease
Diagnosis: haematological, virological, and serology
Management: supportive, prevention through personal protective measures, mosquito control, and vaccination

Viral zoonotic infection causing severe disease in domestic animals and humans
Outbreaks occurred in Africa (Sudan, Kenya) and Arabic peninsula (Saudi Arabia and Yemen)
Zoonotic infection, epizootic (livestock problem)