Posted on 31ST JUL 2017
tagged Ebola, Worldwide

A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases

In this update:
[1] Research
- Hunting-related pathogen exposure
- West African hospitals recovering from outbreak
[2] Vaccines
- Vaccine development
- Phase II vaccine trial

[1] Research
27 Jul 2017: Hunting-related pathogen exposure not just for adult males
[Hunting and slaughtering wild animals in Western and Central Africa can put humans at risk of contracting zoonotic infections, including [Ebola virus disease (EVD)] and Lassa virus. While previous studies have suggested that this risky hunting behavior is mostly limited to adult males, a new study appearing in PLOS Neglected Tropical Diseases [see citation below] finds that women and children also participate.
Complex social and economic factors are known to influence hunting activities in sub-Saharan Africa. Since contact with animal secretions and fluids can occur through bites, scratches and handling organs during the hunting, slaughtering, and cooking of wild game, scientists have worked to understand who is involved in these behaviors and how to educate them on minimizing risks. Previous interventions have mostly focused on adult males.

In the new work, Jesse Bonwitt, of the University of Durham, United Kingdom, and colleagues from the UK and Sierra Leone, carried out a study involving 4 months of fieldwork in Sierra Leone. ...

The researchers found that hunting techniques used in the villages included communal and individual hunts. Hunters relied on nets, snares, traps, guns, and dogs. Descriptions of communal hunts included the ways children were involved, as well as how women played a role, for example helping to flush pray into nets, for instance. Boys often started hunting both alone and in groups from around age 7, and were motivated to do so due to pressure from their family and lack of access to other food, the researchers found. Animal carcasses were always handled with bare hands, and both men, women and children were all involved in preparing and cooking meat, over a fire. Reasons for hunting were complex, and included a need for food, crop protection, income, and social importance. ...-more

Citation: Bonwitt J., Kandeh M., Dawson M., et al. (2017) Participation of women and children in hunting activities in Sierra Leone and implications for control of zoonotic infections. PLoS Negl Trop Dis 11(7): e0005699. https://doi.org/10.1371/journal.pntd.0005699]

29 Jul 2017: West African hospitals still recovering from Ebola epidemic
[West Africa's 2014 Ebola epidemic was the deadliest outbreak of the disease since its discovery in 1976. Liberia was the country hit hardest during the outbreak, reporting between 300 and 400 new cases each week at the epidemic's peak. The World Health Organization [WHO] announced in January 2016 that Liberia was [Ebola virus disease (EVD)]-free, making it the last country to be affected. However, despite the physical absence of the disease, hospitals in Liberia are still dealing with the epidemic's aftermath.

One such hospital is Redemption Hospital in Monrovia, Liberia's capital. Redemption, which is government-run and offers free care to all, was the 1st hospital in Liberia to receive a patient with EVD. Its difficulty in recuperating indicates not only the overwhelming magnitude of the [EVD] epidemic but also the lack of preparation of the Liberian health system to handle it.

Redemption, in particular, lacked the resources it needed to combat the disease. "When [EVD] struck, we lacked protective equipment; running water was sporadic, and there was waste everywhere," Redemption administrator Dominic Rennie said. "We had 2 or 3 patients in each bed as we wouldn't turn people away... conditions were ripe for [EVD ] to spread."

During the outbreak, doctors and other healthcare workers died at alarming rates. Many of Jude Senkungu's colleagues from Redemption, including his roommate, lost their lives. "The 1st thing I felt was shock. ... The 2nd thing was fear and despair," Senkungu said. "The situation felt hopeless ... and [I] could hardly sleep because of the fear that I could also be a case. That's when you really kneel down and pray."

The Redemption workers were overwhelmed by the many incoming [EVD] cases and feared that they, too, would contract the disease. Eventually, they stopped coming into work. The hospital closed temporarily in October of 2014, 4 months after its 1st [EVD] patient had come in.

Thanks to aid and support from various organizations, Redemption was able to get back on its feet only a few months later. Two such organizations, the USAID Office of U.S. Foreign Disaster Assistance and an NGO called International Rescue Committee (IRC), partnered to rehabilitate and reopen Redemption's pediatric and emergency departments. ... -more]

24 Jul 2017: Test-tube immune systems can speed vaccine development
[New technology allows scientists working on new vaccines to combat infectious diseases to test their products' effectiveness on a model immune system in a laboratory without putting the upgraded vaccine into humans.

Researchers have begun building model immune systems using human cells, and this lab technique should make early vaccine trials quicker, safer and cheaper, according to scientists in the United States and Britain involved in this novel approach. The technology also has the potential to be used to mass produce antibodies in the lab to supplement real immune systems that are compromised, or battling pathogens like Ebola.

A report announcing the new "in vitro booster vaccination" technique was published on Mon [24 Jul 2017] in The Journal of Experimental Medicine, published by the Rockefeller University Press. The research project involved produced antibodies that attack strains of tetanus, HIV and influenza.

Selecting specific antibodies
... Before now, when scientists tried to get immune cells in the lab to produce antibodies, the cells would do so indiscriminately, producing all sorts of antibodies, not just the relevant ones. Now scientists are able to get the antibodies they specifically desire by using nanoparticles that connect antigens, the active parts of a vaccine, with molecules that stimulate the immune system.

"We can make these cells very quickly in vitro -- in a Petri dish -- to become antibody-producing cells," said a lead author of the new report, Facundo Batista. "This is quite important," he told VOA, "because until now the only way that this has been done is though vaccinating people." ...more

Citation. Nardin S.A., Fong F., Deantonio J.A. et al. (24 Jul 2017). Novel in vitro booster vaccination to rapidly generate antigen-specific human monoclonal antibodies. J Exp. Med. 2017. 214 (8): 2471-2490. https://doi.org/10.1084/jem.20170633

Abstract. Vaccines remain the most effective tool to prevent infectious diseases. Here, we introduce an in vitro booster vaccination approach that relies on antigen-dependent activation of human memory B cells in culture. This stimulation induces antigen-specific B cell proliferation, differentiation of B cells into plasma cells, and robust antibody secretion after a few days of culture. We validated this strategy using cells from healthy donors to retrieve human antibodies against tetanus toxoid and influenza hemagglutinin (HA) from H1N1 and newly emergent subtypes such as H5N1 and H7N9. Anti-HA antibodies were cross-reactive against multiple subtypes, and some showed neutralizing activity. Although these antibodies may have arisen as a result of previous influenza infection, we also obtained gp120-reactive antibodies from non-HIV-infected donors, indicating that we can generate antibodies without prior antigenic exposure. Overall, our novel approach can be used to rapidly produce therapeutic antibodies and has the potential to assess the immunogenicity of candidate antigens, which could be exploited in future vaccine development. ...-more]

[This new in vitro technique could facilitate development of new vaccines not only to HIV and influenza, but also Ebola virus and more, if the response predicts results when tested in vivo. - Mod.LK]

26 Jul 2017: Ebola Vaccine Trial: 390 Volunteers Confirmed For Phase II
[In the global quest for an Ebola vaccine, Medical Research Council (MRC) in Masaka district has screened 390 people to take part in phase II of the Ebola vaccine trial.

The council received more than 500 volunteers but 390 managed to pass the screening.

Only 5 African countries -- Uganda, Kenya, Ghana, Ivory Coast and Burkina Faso -- are conducting the 2nd phase. This time, Tanzania was excluded after failing at phase I.

In Uganda, key research units including MRC-Masaka and Makerere University Walter Reed Project (MUWRP) are championing the study.
This global effort is meant to create an effective vaccine that could potentially prevent people from catching and dying of [EVD].
Vincent Basajja, the Masaka-MRC Community Liaison Officer, confirms the progress, saying they have not met any challenge in the recruitment of participants. He adds that they have always received good community response towards every study.

According to Dr. Zacchaeus Anywaine, one of MRC/UVRI's leading researchers, the success of phase I gave them the green light to phase II. ...-more]

30 Jul 2017: Advances in Ebola virus vaccination
[Citations. Clarke E.C., Bradfute S.B. (30 Jul 2017). Advances in Ebola virus vaccination. Vaccines and Global Health: Ethics and Policy, Aug 2017. 17(8):781--882 e235-e279 http://www.thelancet.com/journals/laninf/issue/current
http://dx.doi.org/10.1016/S1473-3099(17)30320-1 comment on D G Heppner Jr et al. Safety and immunogenicity of the rVSVÎ"G-ZEBOV-GP Ebola virus vaccine candidate in healthy adults: a phase 1b randomised, multicentre, double-blind, placebo-controlled, dose-response study. Lancet Infect Dis 2017;17: 854-66. http://dx.doi.org/10.1016/S1473-3099(17)30313-4

Comment. The Ebola virus outbreak in western Africa between 2013 and 2016 was the largest and deadliest since the discovery of the virus in 1976. The epidemic provided the impetus to fast-track several promising vaccines into clinical trials during the tail-end of the outbreak, including the rVSVÎ"G-ZEBOV-GP viral vector vaccine, which was used in ring vaccination trials in Guinea.

In The Lancet Infectious Diseases, D Gray Heppner and colleagues report on the safety and immunogenicity of the rVSVÎ"G-ZEBOV-GP vaccine over a 6 log10 dose range. This study shows vaccine dose-dependent total and neutralising antibody titres among study participants, which persisted for up to 360 days. The rVSVÎ"G-ZEBOV-GP vaccine used in the study is a recombinant, replication-competent vaccine based on vesicular stomatitis virus in which the vesicular stomatitis virus glycoprotein (G) has been replaced with the Zaire Ebola virus surface glycoprotein (GP). The Ebola virus surface glycoprotein is the main antigen used in Ebola vaccine development, with the chimpanzee adenovirus (ChAd3)-based vaccine also expressing Ebola virus glycoprotein.

The strength of this study lies in its demonstration of the longevity of neutralising antibody responses after vaccination. Previous studies with this vaccine showed sharp drop-offs in antibody titres after several months, but in this study Ebola virus glycoprotein-specific antibodies were maintained for up to 360 days. Good longevity of immune responses is particularly positive for future development of Ebola virus vaccines, since it could increase the utility of the vaccine for health-care workers and people in endemic regions who are most likely to be exposed to the virus over a prolonged period. ...-more]

[Compiled by: Celeste Whitlow ]

Communicated by:

[A map of the DR Congo can be seen at https://www.independent.co.ug/ebola-in-drc, and a HealthMap/ProMED-mail map of the DRC at http://healthmap.org/promed/p/194.

Maps of the 3 countries affected by the 2014 Ebola outbreak in West Africa can be accessed at:
Liberia http://healthmap.org/promed/p/54
Guinea http://healthmap.org/promed/p/45
Sierra Leone http://healthmap.org/promed/p/46. - Mod.LK]

See Also

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