Question

Research a recent microorganism outbreak in the world. Examples of this could be Ebola or Legionella. Discuss the outbreak, predisposing or precipitating factors for the outbreak, the treatment, safety precautions, virility of micro-organism and the survival rates.

Answer 1

1) The Experience with Ebola :- Non human primates are known to be susceptible to Ebola and have been confirmed as sources of human infections. The role of bats in Ebola virus transmission although suspected since the 1976 Sudan outbreak has yet to be confirmed; the relationships have been hypothesized from Ebola's epidemiological features, which bear a strong resemblance to Marburg. Unfortunately, Towner pointed out, most ecological investigations of Ebola have been initiated after outbreaks were already resolved, and any knowledge of the circumstances under which the index case may have come into contact with the virus is difficult to obtain, because that person is dead and/or unknown. Nearly all of the recent Ebola outbreaks in Gabon and the Democratic Republic of Congo (DRC) have been traced to direct contact with the infected meat of nonhuman primates (which likely died of their infection), but it remains to be determined how those animals became infected with the virus.Ecological niche models of Ebola (and other filoviruses) pursued by several research groups have reached similar general conclusions about where viral reservoirs are likely to exist, based on outbreak locations and the distribution of bat species, vegetation, and rainfall, Towner stated. “While this is interesting and informative in terms of identifying the real hosts, it is not quite granular enough,” he observed.Ecological investigations of local bats, birds, and small vertebrates collected in Gabon and the DRC during repeated Ebola virus outbreaks in both humans and nonhuman primates found three different species of fruit bats to be positive for both immunoglobulin G (IgG) and polymerase chain reaction (PCR); however, no virus was isolated from these animals (Leroy et al., 2005). Similar studies of bats in Ghana found several IgG-positive species including some of the same species identified in Gabon and the DRC but none were PCR positive (Hayman et al., 2012). All three of these bat species are present in West Africa, as well, he noted.As the West African epidemic unfolded, researchers pursued an extensive ecological investigation of the index case, a 2 year old boy reported to have played in a hollow tree found to be infested with the insectivorous bat Mops condylurus. No PCR-positive bats were discovered, nor did they find a linkage to a large mammal die off as had occurred in several previous Ebola outbreaks in Republic of Congo, DRC, and Gabon.
Overall, the inconclusiveness of the antibody evidence linking Ebola virus to M. condylurus suggests these bats may serve as secondary hosts, Towner said. Moreover, he added, the species territory does not coincide with the locations of most known Ebola outbreaks. And since serological cross reactivity has been demonstrated among Ebola viruses, a serologically positive bat found in an outbreak area is not necessarily infected with the outbreak causing strain.

Each Ebola virus type probably resides in a different reservoir host species, Towner hypothesized."For Marburg, we think that Rousettus [aegyptiacus] is it, while I hesitate to say it quite that definitively,” he explained. “There may be other factors involved, but for Ebola Zaire it's probably another species; for Ebola-Sudan it's going to be a different species same with Ebola-Côte D'Ivoire and the others. You know, those viruses perpetuate in those species in the long term.”

The restricted cave biome in which Marburg virus was detected in bats helped narrow the search for its reservoir, Towner observed an advantage researchers seeking the Ebola virus reservoir do not have. That is especially unfortunate if as for Marburg virus the number of active Ebola virus infections in reservoir host populations is low, so hundreds of animals of a single species will need to be tested to find them. “When you take that into account with the fact that there are over 250 bat species in Africa, you can do the math in terms of the number of animals that you then have to test,” he said. As with Marburg virus, active infection may be seasonal, coincident with birth pulses, which are biannual in most African fruit bats, he added.If Ebola virus behaves similarly to Marburg virus, it will spill over into secondary bat hosts that inhabit the same environments, Towner advised.Transmission is likely to be horizontal, and infection will not persist as it does in some rodent viral reservoir species. Viral shedding could occur through the mouth, permitting transmission to other animals by biting and also by feeding from the same piece of fruit. Testing for oral shedding can be done by swabbing, which does minimal harm to bats, many of which are endangered species, he pointed out a fact that also must be borne in mind if they are identified as a reservoir for Ebola, and thereby threatened with eradication.
Genomic Surveillance of Ebola Transmission :- Recent advances in high throughput genetic sequencing allow researchers to track viruses as they spread through host populations, evolving as they go. Stephen Gire of Broad Institute of the Massachusetts Institute of Technology and Harvard University described the application of these methods to reveal how and when the Ebola virus spilled over to humans in West Africa, how many such events occurred, and how the virus evolved as the epidemic unfolded.
The medical team at Kenema Government Hospital in Sierra Leone, where that country's first laboratory confirmed Ebola case was diagnosed, acted quickly to identify more cases through contact tracing, all of whom had attended the funeral of a traditional healer who had treated Guinean Ebola patients, Gire reported. Samples from 12 of the Sierra Leonean patients were sent immediately to Gire's team in Boston, who sequenced and analyzed them within 10 days, using a strategy they had created to track Lassa fever transmission. As the epidemic continued, the researchers continued to sequence patient samples from that hospital, publishing their initial findings (on 114 viral isolates from 78 patients) in August 2014. It was important to make this information available to the scientific community as soon as possible, Gire said, in order to quickly bring as much diverse expertise to its analysis, and thereby, to benefit efforts to quell the epidemic.The key questions of where and how the epidemic began were quickly answered, he noted. Based on viral phylogeny, Gire and coworkers traced the origin of the West African strain to the Ebola-Zaire strain that caused the 1976 outbreak. Comparing genetic differences between the West African isolates and the sequences of other Ebola viruses, and taking into account the rate by which the virus typically undergoes sequence change—its substitution rate—they were able to determine that the specific variant of Ebola-Zaire that sparked the West African epidemic had emerged within the past 10 years in Central Africa, he noted. Further, he said, “We were able to show that it was actually one individual introduction from the animal reservoir into the human population that then was sustained in the population by human-to-human contact afterward.”

Tracing Ebola in Sierra Leone :- Looking to the immediate past, the researchers identified three lineages (comprising 55 mutations) among the Sierra Leonean isolates that distinguished them from three sequences isolated several weeks earlier from Guinean patients, Gire stated. Two of those lineages were present in samples from the initial funeral event, they discovered: about half of those patients had one version of the virus, and half had the other. Perhaps, they hypothesized, the traditional healer had treated a lot of Guinean patients, and had been infected more than once, with the two different lineages; alternatively, one of the funeral attendees might have been infected with a different lineage than the healer—which seems plausible if, as is now suspected, Ebola virus was circulating in Sierra Leone before it was detected in the first laboratory-confirmed patient.Mapping the geographic origins of the three Sierra Leonean lineages, Gire's group reconstructed transmission chains, allowing them to pinpoint where patients had traveled after the funeral, which aided in identifying their contacts. This information also revealed that some patients with broad social networks served as “superspreaders” of Ebola. Since the publication of their initial findings, Gire and colleagues (2014) have generated an additional 150 genomic sequences of Ebola virus isolates from Sierra Leone, which allowed them to continue to track viral transmission and evolution as the epidemic progressed, Gire reported.Over the course of the epidemic, the original lineage, thought to have been imported from Guinea, died off, Gire said. Lineage 2, thought to have arisen in Sierra Leone in April 2014, gave rise to lineage 3 via a single mutation and lineage 3 quickly became dominant and widely distributed across the country. A fourth lineage then arose from lineage 3 via a single mutation and quickly became dominant, much as 3 did from 2. While lineage 2 died out in Sierra Leone, limited evidence suggests it could have reseeded Ebola in Liberia, he added.

2) The Government of the Democratic Republic of the Congo announced today that a new outbreak of Ebola virus disease is occurring in Wangata health zone, Mbandaka, in equateur province. The announcement comes as a long, difficult and complex Ebola outbreak in eastern Democratic Republic of the Congo is in its final phase, while the country also battles COVID-19 and the world’s largest measles outbreak.Initial information from the Ministry of Health is that six Ebola cases have so far been detected in Wangata, of which four have died and two are alive and under care. Three of these six cases have been confirmed with laboratory testing. It is likely more people will be identified with the disease as surveillance activities increase."This is a reminder that COVID-19 is not the only health threat people face,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General. “Although much of our attention is on the pandemic, WHO is continuing to monitor and respond to many other health emergencies.”This is the Democratic Republic of the Congo’s 11th outbreak of Ebola since the virus was first discovered in the country in 1976. The city of Mbandaka and its surrounding area were the site of Democratic Republic of the Congo’s 9th Ebola outbreak, which took place from May to July 2018.“It’s happening at a challenging time, but WHO has worked over the last two years with health authorities, Africa CDC and other partners to strengthen national capacity to respond to outbreaks,” said Dr Matshidiso Moeti, WHO Regional Director for Africa. “To reinforce local leadership, WHO plans to send a team to support scaling up the response. Given the proximity of this new outbreak to busy transport routes and vulnerable neighbouring countries we must act quickly.”WHO is already on the ground in Mbandaka supporting the response to this outbreak, as part of capacity built during the 2018 outbreak. The team supported the collection and testing of samples, and reference to the national laboratory for confirmation. Contact tracing is underway. Work is ongoing to send additional supplies from North Kivu and from Kinshasa to support the government led response.A further 25 people are expected to arrive in Mbandaka tomorrow. WHO is also working to ensure that essential health services are provided to communities despite these emergency events.The Democratic Republic of the Congo’s 10th outbreak of Ebola, in North Kivu, South Kivu and Ituri provinces, is in its final stages. On 14 May 2020, the Ministry of Health began the 42-day countdown to the declaration of the end of that outbreak. New outbreaks of Ebola are expected in the Democratic Republic of the Congo given the existence of the virus in an animal reservoir in many parts of the country.
3) The main risk factors for Ebola virus disease (EVD) include a recent travel to endemic regions, provision of direct care or exposure/processing of blood or body fluids of a symptomatic patient with Ebola virus disease, and direct contact with a dead body in an endemic region without personal protective equipment (PPE).
4) Symptoms of Ebola virus disease (EVD) are treated as they appear. When used early, basic interventions can significantly improve the chances of survival. These include: Providing fluids and electrolytes (body salts) through infusion into the vein (intravenously).Offering oxygen therapy to maintain oxygen status.Using medication to support blood pressure, reduce vomiting and diarrhea and to manage fever and pain.Treating other infections, if they occur.
Antiviral Drugs
There is currently no antiviral drug licensed by the U.S. Food and Drug Administration (FDA) to treat EVD in people.During the 2018 eastern Democratic Republic of the Congo outbreak, four investigational treatments were initially available to treat patients with confirmed Ebola. For two of those treatments, called regeneron (REGN-EB3) and mAb114, overall survival was much higher. These two antiviral drugs currently remain in use for patients with confirmed Ebola.Drugs that are being developed to treat EVD work by stopping the virus from making copies of itself.

5) Wear protective clothing (such as masks, gloves, gowns, and goggles).Use infection control measures (such as complete equipment sterilization and routine use of disinfectant).Isolate patients with Ebola from contact with unprotected persons.

6) Although EBOV RNA can be found in virtually any bodily fluid from patients with acute EVD, historically little is known about viral kinetics in bodily fluids other than blood. EBOV can persist in immune privileged sites (including the central nervous system, eye, urogenital system, placenta and potentially breast milk) and viral persistence may be associated with recrudescent organ specific inflammatory disease (uveitis and meningoencephalitis). Two case reports have documented the development of encephalopathy and meningoencephalitis 13 days and 9 months after clearance of viraemia, respectively, and viable EBOV was detected in the cerebrospinal fluid in one patient. Additionally, in a patient with severe unilateral uveitis, replication competent EBOV was detected in the aqueous humor at high levels 9 weeks after clearance of viraemia.Despite clearance of viraemia, some male survivors continue to shed live EBOV in the semen, thereby posing a public health risk of sexual transmission and reignition of outbreaks.Studies have investigated clusters of EVD cases that occurred sporadically after the peak of the 2013–2016 Western African EVD outbreak, each cluster thought to be initiated by a transmission event involving viral persistence in survivors of EVD, typically in semen.The last flare of the 2013‒2016 Western African outbreak in 2016 was attributed via molecular epidemiology to a sexual transmission event from a survivor at 482 days after disease onset. EBOV RNA was detected in his semen 500 days after EVD onset, although isolation of infectious virus was not possible. These findings led to the implementation of new recommendations regarding the practice of safe sex for survivors of EVD.Despite the detection of EBOV RNA in a few vaginal fluid swabs from female survivors of EVD (up to 37 days after disease onset), no studies have thoroughly evaluated the persistence of EBOV in cervical or vaginal fluid. Though rarely documented, viral persistence has been associated with transplacental transmission.EBOV was detected in a stillborn infant from a mother whose blood was negative for EBOV RNA detected by PCR tests, but who had detectable levels of anti EBOV IgM and anti EBOV IgG antibodies. EBOV RNA was also recovered from breast milk following the death of an infant, suggesting transmission via breastfeeding. In many of these studies, unvalidated diagnostic tests for the detection of EBOV RNA were used, and, therefore, the limits of detection and the repeatability of the assays are unknown. EBOV persistence in immune privileged sites has been reported in NHPs who survive infection; these and future studies will provide crucial insights into the mechanisms of viral persistence.

The chance of survival was 64.7% in 51 patients who had survived 8 days or greater after symptom onset and 86.1% in 36 patients who had survived 12 days or greater after symptom onset. Survival of patients with Ebola virus disease after first day of hospitalization according to age strata.