BY,

DR. B. GURUMURTHY

HOUSE SURGEON

GUIDE-

DR. LAXMIKANT L

ASSOCIATE PROFESSOR,

DEPT OF COMMUNITY MEDICINE

EBOLA –EPIDEMIOLOGY,

DISEASE AND SITUATION ASSESSMENT

AGENT FACTORS

AGENT

• Ebola virus contain single-strand, noninfectious RNA genomes.

• Ebolavirus genomes are approximately 19

kilobase pairs long and contain seven genes

RESERVIOR OF INFECTION

• Fruit Bats.

• Plants, arthropods, and birds have also been considered.

SOURCE OF INFECTION

• The most infectious body fluids are blood, feces, and vomitus.

• Also urine, semen, and breast milk.

• Saliva and tears

HOST FACTORS

AGE• Infection rates are significantly lower in children than in

adults.

• Epidemiologic evidence suggests that children are less likely to come into direct contact with ill patients than adults are.

SEX• No sexual predilection• Men, by the nature of their work exposure in forest and

savanna regions, may be at increased risk of acquiring a primary infection.

RACE Because most cases of Ebola virus infection have occurred

in sub-Saharan Africa, most patients have been black. However, no evidence exists for a specific racial predilection

ENVIRONMENT FACTORS

Studies have shown that low temperature

and high humidity favors ebola virus

infection.

INCUBATION PERIOD• The Ebola incubation period is the period of time

between infection with the Ebola virus and the

appearance of symptoms associated with the

disease.

• Incubation period can be as short as 2 days or as

long as 21 days

MODE OF TRANSMISSION

Person-to-person

Contact with infected animals

Exposure to bats

Nosocomial transmission

PATHOGENESIS

DIFFERENTIAL DIAGNOSIS

Malaria

Dengue

Marburg virus disease

Other viral hemorrhagic fevers

INVESTIGATIONS

Basic Investigation: low platelet count initially decreased white blood cell count followed by an increase in the

white blood cell count elevated levels of the liver enzymes alanine aminotransferase (ALT)

and aspartate aminotransferase (AST) abnormalities in clotting such as a prolonged prothrombin time, partial

thromboplastin time, and bleeding timeSpecific Investigations:Studies for isolating virusRT-PCRTissue culture

Serologic testing for antibody and antigenIgM-capture ELISAIgG-capture ELISAAntigen detection ELISA

DIAGNOSIS

Medical history, especially travel and work history along with exposure to wildlife

Diagnosis is confirmed by isolating the virus, detecting its RNA or proteins, or detecting antibodies against the virus in a person's blood.

Cell culture

PCR

ELISA

During outbreaks most common diagnostic methods are real time PCR and ELISA detection of proteins,

TREATMENT

No Ebolavirus-specific treatment is currently approved.

Treatment is primarily supportive in nature.

It includes :

Minimizing invasive procedures,

Balancing fluids and electrolytes to counter dehydration,

Administration of anticoagulants early in infection to prevent or control disseminated intravascular coagulation,

Administration of procoagulants late in infection to control bleeding,

Maintaining oxygen levels,

Pain management,

Medications to treat bacterial or fungal secondary infections.

EBOLA DISEASE : SITUATION

ASSESSMENT

• LACK OF CAPACITY MAKES INFECTION CONTROL DIFFICULT

• FEAR IS HARD TO OVERCOME

• TRANSMISSION

• VIGILANCE MEANS BETTER DETECTION

EMERGENCY MEETING ON THE ROLE OF EXPERIMENTAL THERAPIES IN OUTBREAK RESPONSE

Barriers to rapid containment of the Ebola outbreak

11 AUGUST,2014

Ebola: Experimental therapies and rumoured remedies

Intense media coverage of experimental medicines and vaccines is creating some unrealistic expectations

WHO has advised that the use of experimental medicines and vaccines under the exceptional circumstances of this outbreak is ethically acceptable.

All rumours of any other effective products or practices are false

15 AUGUST 2014

Ebola situation in Nigeria and Guinea: encouraging signs

In Nigeria

The situation in Lagos, Nigeria, where the first imported case was detected in July, looks reassuring.

The city’s 12 confirmed cases are all part of a single chain of transmission.

There were no further confirmed cases outside the initial transmission chain.

The full recovery to date of one infected contact is additional good news.

19 AUGUST 2014

Ebola situation in Nigeria and Guinea: encouraging signs

In Guinea

Public awareness of the facts about Ebola is higher there than in the other affected countries.

Innovative solutions are being found

But progress is fragile, with a real risk that the outbreak could experience another flare-up.

19 AUGUST 2014

Anecdotal evidence about experimental Ebola therapies

Clinicians working in Liberia have informed WHO that 2 doctors and 1 nurse have now received the experimental Ebola therapy, ZMapp.

The nurse and one of the doctors show a marked improvement. The condition of the second doctor is serious but has improved somewhat.

ZMapp is one of several experimental treatments and vaccines for Ebola that are currently undergoing investigation.

At present, supplies of all are extremely limited.

21 AUGUST 2014

Why the Ebola outbreak has been underestimated

Many families hide infected loved ones in their homes

Others deny that a patient has Ebola

Most fear the stigma and social rejection when a diagnosis is confirmed

Quantities of staff, supplies, and equipment, including personal protective equipment, cannot keep up with the need

Hospital and diagnostic capacities have been overwhelmed

In rural villages, corpses are buried without notifying health officials and with no investigation of the cause of death

The existence of numerous “shadow-zones”.

22 AUGUST 2014

Unprecedented number of medical staff infected with Ebola

To date, more than 240 health care workers have developed the disease in Guinea, Liberia, Nigeria, and Sierra Leone, and more than 120 have died.

The factors that help explain the high proportion of infected medical staff:

Shortages of personal protective equipment or its improper use

Few medical staff for such a large outbreak

The compassion

WHO estimates that, in the three hardest-hit countries, only one to two doctors are available to treat 100,000 people

Increase in the level of anxiety: if doctors and nurses are getting infected, what chance does the general public have?

25 AUGUST 2014

Ebola situation in Port Harcourt, Nigeria

THE RESPONSE:

Nigerian health workers and WHO epidemiologists are monitoring more than 200 contacts. Of these, around 60 are considered to have had high-risk or very high-risk exposure.

An Ebola Emergency Operations Centre has been activated, with support from the US Centers for Disease Control and Prevention.

A mobile laboratory, with RT-PCR diagnostic capacity, is set up and functional.

A 26-bed isolation facility for the management of Ebola cases is in place, with plans for possible expansion.

WHO has 15 technical experts on the ground. Twenty-one contact-tracing teams are at work and adequate transportation. Two decontamination teams are equipped and operational, as is a burial

team. Screening is under way at domestic and international airport gates. Social mobilization efforts have been stepped up, initially targeting key

community and religious leaders.

3 SEPTEMBER 2014

Ebola situation in Liberia: non-conventional interventions needed

THE RESPONSE:Liberia yields 3 important conclusions that need to shape the

Ebola response in high-transmission countries. First, conventional Ebola control interventions are not having an

adequate impact in Liberia, though they appear to be working elsewhere in areas of limited transmission, most notably in Nigeria, Senegal, and the Democratic Republic of Congo.

Second, far greater community engagement is the cornerstone of a more effective response. Where communities take charge, especially in rural areas, and put in place their own solutions and protective measures, Ebola transmission has slowed considerably.

Third, key development partners who are supporting the response in Liberia and elsewhere need to prepare to scale up their current efforts by three- to four-fold.

8 SEPTEMBER 2014

Ebola situation in Senegal remains stable

Preventing further transmission of Ebola:

Aggressive efforts to identify additional contacts continue The investigation and response teams face difficulties in

keeping close contacts in isolation for the 21-day monitoring period.

Contacts have remained in their homes, usually with their families, where they are checked twice daily for symptoms and tested if symptoms develop.

Some contacts have resisted monitoring, but none has been lost to follow-up.

Although Senegal has banned all flights from other affected countries, road travellers from Guinea and elsewhere can cross the country’s porous borders.

WHO has repeatedly advised countries not to issue travel bans To support the global response, Senegal has agreed to open a

humanitarian corridor to facilitate the transport and delivery of international personnel and supplies to affected countries.

12 SEPTEMBER 2014

Experimental therapies: growing interest in the use of whole blood or plasma from recovered

Ebola patients (convalescent therapies)

Convalescent therapy was first used for a young woman infected with Ebola in the Democratic Republic of Congo (then Zaire) in 1976 – the year the virus first emerged

During the 1995 Ebola outbreak in Kikwit, Democratic Republic of Congo, whole blood collected from recovered patients was administered to eight patients

In the current outbreak, convalescent therapies have been used in a few patients. In one well-known case, an American doctor, who became infected while

working in Monrovia, Liberia, received whole blood from a recovered patient

26 SEPTEMBER 2014

CONT..

As the epidemic worsens, interest in convalescent therapies grows

The number of cases continues to grow exponentially

Good supportive clinical care is becoming increasingly difficult to implement.

WHO is currently holding discussions with health experts in the Democratic Republic of Congo, Guinea, Liberia, Nigeria, and Sierra Leone with aim to identify practical needs for implementation

26 SEPTEMBER 2014

How does WHO declare the end of an Ebola outbreak?

For WHO to declare an Ebola outbreak over, a country must pass through 42 days, with active surveillance demonstrably in place, supported by good diagnostic capacity, and with no new cases detected. Active surveillance is essential to detect chains of transmission that might otherwise remain hidden.

Incubation period

The period of 42 days, with active case-finding in place, is twice the maximum incubation period for Ebola virus disease and is considered by WHO as sufficient to generate confidence in a declaration that an Ebola outbreak has ended.

14 OCTOBER 2014

The outbreak of Ebola virus disease in Senegal is over

Senegal is free of Ebola virus transmission

Factors that contributed to success:

Strong political leadership at the highest level.

Early detection and response, aided by a detailed plan and a quickly-activated National Crisis Committee.

Stepped up surveillance, especially at the country’s many entry points by road.

Rapid mobilization of resources from both domestic and international sources; solid preparedness plans are thought to have earned the confidence of donors.

Support from operational partners, including WHO.

17 OCTOBER 2014

CONT..

Nationwide public awareness campaigns that made good use of media experts, embedded in the Ministry of Health and Welfare and allowed to closely observe its emergency actions, and local radio networks.

Deliberate and heavy emphasis on multisectoralcollaboration among all relevant government ministries, backed by community engagement every step along the way.

Direct support to patient contacts as a strong incentive for cooperation and compliance, through the provision of social support in the form of money, food, and psychological counselling.

Support for reintegration of the recovered patient into a society that could understand why he posed no risk of contagion to others.

Nigeria is now free of Ebola virus transmission

What accounts for this great news? The country’s strong leadership and effective coordination of the

response. The Nigerian response to the outbreak was greatly aided by the

rapid utilization of a national public institution (NCDC) and the prompt establishment of an Emergency Operations Centre, supported by the Disease Prevention and Control Cluster within the WHO country office.

Another key asset was the country’s first-rate virology laboratory affiliated with the Lagos University Teaching Hospital.

In addition, high-quality contact tracing by experienced epidemiologists expedited the early detection of cases and their rapid movement to an isolation ward, thereby greatly diminishing opportunities for further transmission.

20 OCTOBER 2014

REFERENCES

emedicine.medscape.com

en.wikipedia.org

www.forbes.com

www.who.int

www.uptodate.com

www.afro.who.int