VIRAL HAEMORRHAGIC FEVERS BY DR UCHE UNIGWE

Lassa fever Yellow fever Marburg/Ebola HF Dengue HF Crimean- Congo HF Hanta virus HF

LASSA FEVER- Background Acute viral illness of 1- 4 weeks duration transmitted by RNA virus called Lassa fever virus. Endemic in Guinea, Liberia, Sierra Leone and Nigeria. Multimammate mouse of Mastomys specie as reservoir Transmitted through aerosol or direct contact with excreta of infected rodents deposited on surfaces or food. Person to person through sexual contact via semen or contact with secretions of infected persons

Background contd. All ages are susceptible. Incubation period days Infection occurs commonly during the acute febrile period. 80% of infections are mild or asymptomatic. 15% with severe infections may die. Duration of immunity is long lasting but notlife long.

LASSA FEVER; Diagnostic dilemma Particularly difficult for the following reasons: Clinical features of Lassa fever are non-specific. Many infections are sub-clinical. Early clinical manifestations are often indistinguishable from those of many other febrile illnesses. Thus a high index of suspicion is needed to make the diagnosis. Late diagnosis & missed out cases are a common feature

VARIED SYMPTOMATOLOGY Fever, headache, chills, pharyngitis, facial swelling, anorexia, lethargy, weight loss, severe abdominal pain, maculopapular rash, blood pressure changes, sudden hypotension, swollen neck, swollen face, swollen eyes, tinitus, mucosal bleeding, heart rate changes, deafness, conjunctivitis, pleural effusion, ascites, encephalopathy, spontaneous abortion, back pain, diarrhea, cough.

Classification of signs/symptoms MAJOR CRITERIA ABNORMAL BLEEDING SWOLLEN NECK/FACE RED EYES /CONJUNCTIVITIS SPONTANEOUS ABORTION DEAFNESS DURING ILLNESS LOW BLOOD PRESSURE/SHOCK MINOR CRITERIA SORE THROAT HEADACHE LEUCOPENIA[< 400/mm] NAUSEA & VOMITING ABDO.PAIN/DIARRHOEA COUGH/PLEURAL EFFUSION ASCITES/WEAKNESS PROTEINURIA BACK PAIN.

PRESUMPTIVE DIAGNOSIS Suspect Case : Patient with fever[37.8 C or more] not responding to anti-malarial and antibiotics. Possible Case : Persistent fever with 2 or more minor criteria and known contact with Lassa fever cases. Probable Lassa fever :Persistent fever with any of the major criteria above. Fever, sore throat,retrosternal pain are useful clinical predictors for diagnosis.

Clinical Symptoms Days 1 – 3 Days 4 – 7 After 7 days After 14 days General malaise & weakness, high fever >39C constant with peaks of 40 – 41 C. Sore throat, back pain, chest pain, red eyes, diarrhea, low BP, cough, anemia, etc. Facial edema, bleeding, convulsions, confusion. Death

SUPPORTIVE INVESTIGATIONS FBC – Lymphocytosis and/or monocytosis. LFT – Raised transaminases. Poor prognosis if AST is markedly raised. Prothrombin Time --- Prolonged Urinalysis --- Proteinuria ? Lymphopenia. ? Thrombocytopenia.

Diagnostic investigations IgM antibody capture or antigen detection via ELISA. Detection of viral genome via PCR./viral culture IgG seroconversion via ELISA. Inactivate specimens by heating to 60 C for 1 hour. Disinfect with sodium hypochlorite.

Treatment I.v Ribavirin at 33mg/kg stat –day 1 Then 16mg/kg 6 hrly – day 2- 5 Then 8mg/kg 8 hrly -day Supportive treatment Antibiotics for co-infections Barrier nursing.

PROPHYLAXIS AND CHALLENGES PROPHYLAXIS - Close contact with confirmed case during 2 wks prior to onset of symptoms. - Contacts during symptomatic period. -Contacts during the 8 wks after recovery. - Oral ribavirin given for 7-10 days CHALLENGES Developing containment, treatment & vaccine strategies. Developing & making available immunologic & molecular tools for more rapid diagnosis. Offering effective preventive public health advice for avoiding infection