By Adil E. Shamoo, Ph.D. (guest blogger)
In 2014, the spread of Ebola topped the headlines. While other issues have supplanted Ebola for the time being, the risk remains as the virus continues to claim victims. A viable Ebola policy that contains the spread must be put into place.
Ebola is transmitted through direct contact with body fluids, blood, and skin. Body fluid droplets remain viable for a few hours; the most infectious period is when the patient is exhibiting severe symptoms with high fever, vomiting and diarrhea. The CDC, as of January 7, 2015 informed us that in West Africa, there are 21,086 cases and 8,289 have died from EbolaWorldwide estimates, if under-reporting is taken into consideration, are that the number of Ebola infections is as high as 1.5 million cases. 450 healthcare providers in West Africa have contracted the Ebola virus and 244 have died. In the U.S., ten healthcare providers were infected and treated; two died. The life-cycle of the Ebola virus in humans is 21 days. With a fatality rate of 50-80 % , the fear of highly infectious Ebola is understandable. The incubation period is 11.4 days. The WHO data indicates that the disease continues to spread rapidly.
According to the World Health Organization’s latest information on prevention and control of Ebola infection, the primary goal is to reduce human contacts with Ebola patients- especially with their body fluids. The necessity of identifying Ebola patients, monitoring the health of contacts for 21 days, separating the healthy from the sick are encouraged along with personal hygiene precautions.
Isolation, Quarantine, Monitoring and Travel Restrictions
There would be no crisis if drugs and vaccines to combat the disease were available to use, but none exist yet. Thus, the current Ebola epidemic requires specific measures to prevent the spread of the disease. Isolation and quarantine, two traditional measures of controlling disease can be used effectively to control Ebola, along with careful monitoring. Isolation is the voluntary act of avoiding any contact with the outside world for the designated period. Monitoring can be performed by the individual possibly affected or by another person and has been used in this epidemic with efficacy. Quarantine is the mandatory isolation from any contact with the outside world with professional monitoring. Thus quarantine is a coercive process used by governments in emergencies to safeguard public health and safety. Several healthcare providers who took care of the first U.S. patient, Mr. Duncan, became ill and were quarantined in hospitals and so far all have survived. All other healthcare providers who came in contact with Ebola patients were isolated for 21 days and were released.
Six states-New Jersey, New York, Maine, Georgia, California and Connecticut (on a case by case basis) – have instituted quarantine for the healthcare providers who have taken care of Ebola patients in West African countries.
1976 Epidemic in Zaire
The first official WHO report on Ebola in 1978, Report of an International Commission in 1978, was for the epidemic in Zaire, in 1976. (One has to keep in mind that the report is based on limited epidemiological data on a limited number of patients). The report indicates that the Ebola-contaminated injection of an anti-malaria drug was the main culprit and as a result it was able to accurately identify the date the virus was introduced into the population affected. Using the day of the needle injection as time zero of the introduction, it was noted that on day 2 to 7, signs of virus infection appeared. The non-specific signs and symptoms such as fever, headache, and sore throat appeared on day 3 to 4. Within an average of 6.3 days, severe symptoms such as gastrointestinal bleeding and severe sore throat appeared. The virus had a 12 day cycle. In one patient, the viral load peaked at around five days.
Infectious period
The most recent data from WHO are consistent with the 1976 epidemic in Zaire except the virus life-cycle in ‘76 was 12 days as compared to the current 21 days. The recent report indicates that 95 % of patients have signs and symptom of the disease in 21 days and thus the conclusion that the life-cycle of the virus is 21 days. The incubation period, with signs and symptoms, is 11.4 days and the serial interval (time to transmission to the next person) is 15.3 days. It is important to note that the onset of signs and symptoms appear in a Bell shaped curve with an average of 11.4 days. The appearance of symptoms has a bandwidth of a week or two with a varied amount of viral load well below compared to the period associated with the appearance of severe symptoms of infection. It is true that the limited data so far from observation of cases derived from the period of time below the infectious peak is zero. However, the observation data are not sufficient and no specific study has been conducted to observe the transmission of the disease in this period. Finally, it would be best if the transmission of the disease during the two-week period prior to the peak of transmission where confirmed contact was studied, and the type of contact (e.g., sex, handshake) was reported during that period.
A further complicating factor is sexual transmission. The virus remains in the semen for up to three months after recovery. The CDC recommends men abstain from sex for three months after recovery. Virologist Alan Schmalhohn of the University of Maryland is quoted on a recent NPR story as saying “Sexual transmission is a significant risk”. In the same NPR story, the Ministry of Health in India proclaims that they are quarantining patients with Ebola until their semen is free of the virus.
For U.S. asymptomatic health care providers treating Ebola patients in West Africa and returning to United States, it is ethically justified to Quarantine them for up to 21 days because they may be infected. In addition, these healthcare providers should understand that they have an additional ethical duty to do no harm to the public from this deadly virus. The CDC recommends correctly that men should abstain from sex for three months. Doctors Without Borders recommends the use of condoms for 90 days – a lesser certain method for protection.
All US citizens should be banned from travelling to and from West African nations except for those with compelling reasons to travel (including healthcare personnel).. The isolation of US citizens who come in contact with Ebola patients for up to 21 days is warranted. A travel ban for all West Africans from affected areas should be imposed except for essential personnel. If further data become available, a re-assessment of isolation and quarantine can be conducted to determine whether the isolation/quarantine policies should be removed or shortened.
Editor’s Note: Parts II and III will be published next week.