LASSA FEVERPRESENTED BY

PRITHI SHALINI.P,CLINICAL INSTRUCTOR

Faculty of nursing,Sri Ramachandra Hospital

Presentation outline Introduction History about Lassa fever Definition Epidemiology , Facts Lassa virus structure Mode of transmission Risk of exposure Signs and Symptoms Diagnostic evaluation Medical management Prevention and control Prognosis Conclusion

INTRODUCTION

• Two Missionary nurses

• 1969,Lassa town

• Collaborated with Yale Arbo virus Research Unit

• Rodent- Mastomys genus(i.e. ,multimammate mouse)

• Location- West Africa

• Habitat-Savanna , forest clearing

• Season-January to April

• Human contact – Primarily within houses

HISTORY Lassa Mission hospital in lassa town BORNO State ,Northeastern Nigeria 19th January 1969 LAURA WINE ,65 yrs, American Missionary

Nurse Evangel Hospital ,Dr.Hamer

Laura wine

Evangel hospital in lassa town Charlotte shaw, American Missionary Nurse Head nurse PENNY PINNEO Dr. Jeanette Troupe CHARLOTTE SHAW

  ARBOVIRUS Research laboratory in Yalea New virus was isolated by a team of Scientist

led by jordi Casals The virus that was isolated was named Lassa

Virus

HISTORY CONTD……..

Penny pinneo survived and returned to Nigeria to continue her missionary work

PENNY PINNEO

 

epidemiology• Endemic in areas of west Africa ,including Nigeria , Liberia , Sirria leone and

Guinea .• Estimated 3,00,000 – 5,00,00 infections /year ,with 5000 deaths

At risk population of 51 million, – 3 million annual illness and – annual death of 58,330. (Richmond DJ, Baglole DJ. Lassa fever: epidemiology, clinical features, and social consequences. Br Med J 2003; 327:1271-5). 

• Lassa fever at Germany and Newyork in the year of 2000

Facts 80% - no observable symptoms

20% - severe multisystem disease

Affects all age groups and both sexes

Seasonal clustering : late rainy and early dry season

Have a potential usage of bioterrorism (US-NIAID)

DEFINITION Lassa fever or Lassa hemorrhagic fever (LHF) is an acute viral hemorrhagic fever caused by the Lassa virus and first described in 1969 in the town of Lassa, in Borno State, Nigeria. Lassa virus is a member of the Arena viridae virus family.

LASSA VIRUS

Structure Arenaviridae family

spherical

Lipid membrane single-stranded RNA

The lassa carrier

Mastomys natalensis LASSA HOST

MODE OF TRANSMISSION

Inhalation of aerosolized virus

Ingestion of food or materials contaminated by infected

rodent excreta

Catching and preparing mastomys as a food source

1. RODENT -TO- HUMAN TRANSMISSION

MODE OF TRANSMISSION cond…

Direct contact with blood ,tissues , secretions or

excretions of infected humans

Needle stick or cut

Inhalation of aerosolized virus

2. HUMAN –TO- HUMAN TRANSMISSION

3 . OTHER TRANSMISSION

Zoonotic Sexual transmission Through pregnancy

Risk factors Persons at greatest risk are those living in Rural areas Communities with poor sanitation Crowded living conditions Health workers in the absence of proper

barrier nursing And infection control

practices

Pathogenesis of lassa fever Exact method of pathogenesis is not understood

• Endothelial cell damage /capillary leak

• Vascular damage

• Platelet dysfunction

• Disorder of coagulation

• Suppressed cardiac function

• Cytokines and other soluble mediaters of shock and inflammation

• Immunological impairment

• End organ damage

Clinical MANIFESTATIONS

After a 6 TO 21 days INCUBATION PERIOD, an acute illness with multi-organ develops.

- Initial non specific symptoms of fever facial swelling muscle fatigue conjunctivitis mucosal bleeding

Clinical manifestations cont… Richmond & baglole (2003)

stage 1 (days 1-3) General weakness and malaise , fever ,about 39 ۫c constant with peaks of 40 ۫۫c - 41 ۫۫c Stage 2(days 4-7) Sore throat ,headache, abdominal pain, conjunctivitis, nausea and vomiting, diarrhea, productive cough, Proteinuria, hypotension and anemia

Stages 3 (after 7 days) Facial edema ,convulsion ,mucosal bleeding (mouth,nose,eyes) internal bleeding and confusion or disorientation

Stages 4 (after 14 days ) Coma and death

Major signs BleedingSwollen neck or face Conjunctivitis Petechial hemorrhage Sub conjunctiva hemorrhage Persistent hypotension

Minor signs Head ache

Sore throat, cough

Generalized myalgia

Arthralgia

Vomiting

Diarrhoea

Profuse weakness

signs of lassa fever

signs AND SUMPTOMS of lassa fever

• Significant cause of pediatric hospitalizations in some areas of west Africa

• Signs and symptoms most often similar to adults “Swollen baby syndrome”-

-Edema -Abdominal distension -Bleeding -Poor prognosis

Lassa fever in children and infants

Malaria Typhoid fever Streptococcal pharyngitis Leptospirosis Bacterial or viral conjunctivitis Entero virus infection Viral hepatitis(anicteric hepatitis) Cholrea Meningococcemia and gram negative sepsis Rickettsial diseases Others VHFs(Ebola/Marburg ,Rift valley

fever ,Chikungunya,Zika )

Differential diagnosis

DIAGNOSTIC EVALUATION Lassa virus infections can only be diagnosed definitively using the

following tests; History collection Physical examination CBC-mild leucopenia and lymphopaenia/mild

thrombocytopenia Urinalysis-Proteinuria RFT - High BUN LFT-(AST>150U/L) Virus isolation by cell culture-virus may be cultured from

blood ,urine and throat (7 -10 days)

Reverse transcriptase polymerase chain reaction (RT-PCR)assay –Being used experimentally

Serology –IgM is detected by ELISA .Using combination of antigen and IgM antibody tests , it was shown that virtually all Lassa virus infections can be diagnosed early

Post mortem – Immunohistochemistry on tissue specimens

-Per arteriolar lymphocytic sheath -Hepatic necrosis -Mononuclear phagocytosis

DIAGNOSTIC EVALUATION CONTD…..

Isolation

Infection control

Antiviral drug therapy –RIBAVIRIN shown to reduce mortality 5-10 fold if given intravenously within 6 days of the clinical illness , loading dose ; IV 30 mg/kg(max,2g),followed by 15 mg/kg 6hrly for 4 days(max 1g),then 7.5mg/kg(max.500mg)8hrly for 6 days

Dilute Ribavirin in 150 ml of 0.9%NS and infuse slowly

No convincing evidence that oral Ribavirin delays or prevents Lassa fever

Supportive care

Medical management

Deafness (1/3 of cases),permanent Hypovelemic shock Respiratory distress Congestive heart failure may occur

10 -20 % of patients experience late neurologic involvement characterized by intention tremor of the tongue and associated speech abnormalities. In severe cases , There may be tremors of the extremities, seizures and delirium. the cerebrospinal fluid is normal

Anuria Death

COMPLICATIONS OF LASSA FEVER

There is no injection or vaccine to prevent Lassa fever. To prevent Lassa fever, we must prevent its spread by rats

Prevention and control

Prevention AND CONTROL

Village –based programs for rodent control and avoidence Hospital training programs to avoid nosocomial spread;

barrier nursing manual Diagnostic technology transfer Research is currently underway to develop a vaccine Clean environment Good health seeking behavior Proper hand washing Health education via Media, Pamphlets etc… Proper Nutrition

Prevention AND CONTROL

1. Isolation2. Disinfection3. Surveillance 4. Rodent control

Prevention AND CONTROL1. Isolation

Strict barrier nursing techniques with PPE No visitors into the ward Wear protective articles of clothing such as mask,

goggles, gloves and gown when caring for patients and isolating lassa patients from contact with unprotected persons until they recover

Laboratory teat for lassa should be performed in a high containment facility with all available precaution taken ,including use of gloves and biosafety cabinets

Prevention AND CONTROL2.Disinfection

The excreta ,blood and sputum of the patients as well as all objects which the patient come into contact and all laboratory equipment used to test the patient’s blood ,should be disinfected with 0.5% sodium hypo chloride solution or 0.5%phenol with detergent .

Boiling Sterilization by autoclave Fumigation Incineration -Proper disposal of sharps and clothing of sick

individuals

Prevention AND CONTROL3.Survillence

Fever 39 ۫c Unreported and undiagnosed cases

Avoid attending or hosting public gatherings / events

unless strictly indicated (incase of an out Break)

Enact border laws to curb spread

Early self referral

Prevention and control

Restrict entry of rats into the house

Keep the home clean to discourage rodents from entering

Isolate food supplies from rodents

Use rodent proof containers for food

Don’t use the rodent as a food source

Eliminate habitats for rats , and “Minimize activities that produce aerosols” that

might contain rodent excreta

Educating the population about rodent control in and around their homes and

villages

4.Rodent Control

REHABILITATION

Psychotherapy

Physiotherapy

Organ transplant

Hyperthermia related to infection as evidenced by temperature (100 F) as evidenced by vital signs.

Nursing interventions:

NURSING management

•Monitor temperature at least every 2 hours.•Monitor blood pressure, pulse, and respiration.•Monitor level of consciousness.•Monitor WBC, Hb, Hct.•Monitor intake and output.•Give antipyretic.•Provide treatment to overcome the cause of fever.•Provide intravenous fluids

About 15-20% of hospitalized lassa fever patients will die from the illness

The overall mortality rate is estimated to be 1% but during epidemics , mortality can climb as high as 50%

The mortality rate is greater than 80% when it occurs in pregnant

Women during their third trimester ; fetal death also occurs in nearly all those cases

Termination of pregnancy decreases the risk of death of the mother

prognosis OF LASSA FEVER

Review of the Literature and Proposed Guidelines for the Use of Oral Ribavirin as Post exposure Prophylaxis for Lassa Fever. Clinical Infectious Diseases, Volume 51, Issue 12, Pp. 1435-1441.

Oral administration of the antiviral drug ribavirin is often considered for post

exposure prophylaxis, but no systematically collected data or uniform guidelines

exist for this indication. Furthermore, the relatively low secondary attack rates for

Lassa fever, the restriction of the area of endemicity to West Africa, and the

infrequency of high-risk exposures make it unlikely that controlled prospective

efficacy trials will ever be possible. Recommendations for postexposure use of

ribavirin can therefore be made only on the basis of a thorough understanding and

logical extrapolation of existing data. 

,

Daniel G. Bausch1, Christiane M. Hadi1, Sheik Humarr Khan3

conclusionThe rat is a palatable meal particularly among the resource poor population ; a friend

It carries a deadly virus which is responsible for tension ,illness and death among Nigerians and other West African countries; a foe

It is sad to lose a palatable meal to a rat but sadder when loved ones lose you to a rat

ReferencesWHO websiteCDC GuidelinesPANO(2006)Richmond and baglole(2003)Morens et al (2004)Becker and barry (2009)Punch news papperPalmer (2011)