April 7, 2014
WHO Reports On Ebolavirus, Emergency Response And Disease Transmission
Lawrence LeBlond for redOrbit.com - Your Universe Online
As of April 4, the Ministry of Health of Guinea has reported to the World Health Organization (WHO) 143 clinically compatible cases of infection from Ebolavirus disease (EVD). Of these, 54 have been laboratory confirmed by polymerase chain reaction (PCR).
The total number of deaths associated with this outbreak stands at 86 – a case fatality rate of about 60 percent – of which sixteen have been lab-confirmed as EVD deaths, 65 are listed as probable cases and five are suspected cases.
According to the WHO, several new cases have been reported from the Guinea provinces of Conarky, Guekedou and Macenta, and 23 patients are currently in isolation units. The most recent lab-confirmed case is from April 3.
A previous report listed 14 healthcare workers as possibly becoming infected by EVD, of which eight died. There has been no increase in this number since that report. Eleven of the affected HCWs have been lab-confirmed.
WHO said contact tracing continues, with 623 contacts requiring medical follow-up, including 74 new contacts identified on April 3. WHO noted that 49 have been released from observation as they have remained symptom-free after the 21-day incubation period expired since last exposure.
WHO, working with technical partners in the Global Outbreak Alert and Response Network (GOARN), has deployed field lab support, as well as a number of experts in anthropology, epidemiology, logistics, clinical case management and infection prevention and control and outbreak coordination to support the emergency response efforts in Guinea.
In response to the EVD outbreak in Guinea, Liberia has been scaling up activities to prevent the further spread of the disease there.
“The National Task Force is conducting daily coordination meetings with response partners. WHO continues to provide technical expertise to the MOHSW, including public communications, providing a high level briefing on EVD prevention and control to the joint session of both houses of parliament and mobilising experts in epidemiology and infection prevention and control,” WHO said in a statement, regarding Liberia’s activities.
“The WHO Country Office in Liberia is working closely with the MOHSW to carry out needs assessments in areas such as procurement and the supply chain for critical materials and equipment need in the response to the outbreak. WHO is also working with the health information systems team at the MOHSW to further develop templates for case-based data collection and to track technical assistance. Additional deployments of regional experts, and partners in GOARN, are planned to support coordination activities, infection prevention and control, risk communications and social mobilization,” it added.
A number of organizations, including WHO, UNHCR, MSF Save the Children and others, are providing medical supplies and equipment, as well as protective equipment in response to the outbreak response efforts. Also, seven isolation units have been established in five countries and Doctors Without Borders staff are conducting training for healthcare personnel in affected regions.
Previously, two fatal cases had been reported in Sierra Leone, both from the same family who visited Guinea. There have been no new cases attributed to persons from this country. However, the office of the Chief Medical Officer in Sierra Leone is continuing investigations for possible suspected cases.
Ministry of Health officials from both Guinea and Sierra Leone have conducted border crossing visits to sensitize border authorities about the current prevention and response plans in regards to EVD. As well, public health officers are visiting border communities to support mobilization activities. Metabiota Laboratory in Kenema, Sierra Leone has established a full suite of ebolavirus-specific assays and diagnostic tools for emergency response.
EVD, which was formerly known as Ebola hemorrhagic fever, has now been confirmed to be caused by a strain of ebolavirus with very close homology (98 percent) to the Zaire ebolavirus. This has been the first time the disease has been detected in West Africa. The first cases were detected from forested areas in southeastern Guinea, quickly spreading throughout the country and even crossing borders.
The ebolavirus genus is one of three members of the Filoviridae family (filovirus) – the other two members are marburgvirus and cuevavirus. There are five distinct species of ebolavirus: Bundibugyo ebolavirus (BDBV); Zaire ebolavirus (EBOV); Reston ebolavirus (RESTV); Sudan ebolavirus (SUDV); and Taï Forest ebolavirus (TAFV). BDBV, EBOV and SUDV have been associated with large ebolavirus outbreaks in Africa. Samples from the most recent outbreak have tested positive for EBOV.
It is assumed that fruit bats are the most common natural host of ebolavirus in Africa. It is further assumed that most wildlife that suffer from ebolavirus is the result of contact with saliva or feces from infected fruit bats. Humans get the disease by contact with these infected animals, such as pigs or monkeys, or by direct contact with infected bats.
People can also get the disease from the slaughtering of infected animals or through consumption of blood, milk, or raw or undercooked meat.
Once the virus becomes humanized, it is transmissible through direct contact with blood, secretions or other bodily fluids of infected persons. Transmission is also possible from contaminated needles and other medical equipment used on infected persons.
EVD is associated with a case fatality rate of up to 90 percent. It is a severe acute viral illness often characterized by the sudden onset of fever, intense weakness, muscle pain, headache, nausea and sore throat. Soon after, vomiting, diarrhea, and impaired kidney and liver function follow, along with internal or external bleeding.
The incubation period for onset of symptoms is between two and 21 days. People who are infected but do not show symptoms of EVD can still remain infectious for up to 61 days, according to experts.
According to the WHO, other more common diseases should not be overlooked when considering an EVD diagnosis. Malaria, typhoid fever, shigellosis, cholera, leptospirosis, plague, rickettsiosis, meningitis, hepatitis and other viral hemorrhagic fevers may all have similar symptoms that are also associated with EVD. A definitive diagnosis for EVD is made through laboratory testing.
If EVD is diagnosed, death is likely within four days. If patients live beyond the fourth day, it is possible they can recover, especially if treated with oral rehydration with solutions containing electrolytes or intravenous fluids. There is no vaccine available to prevent EVD from infecting humans.
Raising awareness is the only protective measure that can be taken to reduce human transmission of the disease. Close unprotected physical contact with infected patients should be avoided at all costs. Nearly all transmission of the virus to healthcare workers in Guinea were reported because basic infection control measures were not observed.
In cases that result in death, proper safe burial is key to avoiding further spread of the disease, as it remains highly transmissible even after death.
“WHO encourages countries to strengthen surveillance, including surveillance for illness compatible with EVD, and to carefully review any unusual patterns, in order to ensure identification and reporting of human infections under the IHR (2005), and encourages countries to continue national health preparedness actions,” the UN-based organization said in a statement.
WHO says it does not recommend any travel or trade restrictions be applied to the affected region with respect to this outbreak at this time.