PLoS NTDS: Prioritizing Surveillance of Nipah Virus in India

Credit: Current Opinion in Virology 2019,34:79–89

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While long known to carry rabies, over the past 25 years bats have gained new respect for hosting - and occasionally transmitting - dozens of viruses capable of infecting humans. EcoHealth Alliance published a letter in Nature (Host and viral traits predict zoonotic spillover from mammals) in 2017 providing the first comprehensive analysis of viruses known to infect mammals.

From their website summary: 

The study shows that bats carry a significantly higher proportion of viruses able to infect people than any other group of mammals; and it identifies the species and geographic regions on the planet with the highest number of yet-to-be discovered, or ‘missing’, viruses likely to infect people. This work provides a new way to predict where and how we should work to identify and pre-empt the next potential viral pandemic before it emerges.

Indeed, there is evidence that Many Human Viruses May Have Jumped from Bats, including mumps and measles, and that zoonotic viruses such as Ebola, Marburg, SARS, MERS-CoV, and Nipah all originated in bats.

Aside from rabies - which kills nearly 60,000 each year around the world - the two bat diseases of greatest concern are MERS-CoV and Nipah, as both have shown limited human-to-human transmission.  

The Nipah virus - normally carried by fruit bats common to S.E. Asia - was only first identified 20 years ago after an outbreak in Malaysia, which spread from bat to pigs - and then from pigs to humans - eventually infecting at least 265 people, killing 105 (see Lessons from the Nipah virus outbreak in Malaysia).

The WHO Nipah Summary reads:

Key facts

• Nipah virus infection in humans causes a range of clinical presentations, from asymptomatic infection (subclinical) to acute respiratory infection and fatal encephalitis.
• The case fatality rate is estimated at 40% to 75%. This rate can vary by outbreak depending on local capabilities for epidemiological surveillance and clinical management.
• Nipah virus can be transmitted to humans from animals (such as bats or pigs), or contaminated foods and can also be transmitted directly from human-to-human.
• Fruit bats of the Pteropodidae family are the natural host of Nipah virus.
• There is no treatment or vaccine available for either people or animals. The primary treatment for humans is supportive care.
• The 2018 annual review of the WHO R&D Blueprint list of priority diseases indicates that there is an urgent need for accelerated research and development for the Nipah virus.

While most of the Nipah action has been centered in Bangladesh for the past 20 years, last summer, in Nipah Transmission In Kerala Outbreak, we looked at the apparently robust household and nosocomial transmission of the Nipah virus in Southern India.

Thiat outbreak was fortunately stopped at 19 cases, and declared over on July 1st, 2018, but a fresh case was reported earlier this month in the same region (see India: MOH Confirms Nipah Case In Kerala) sparking new concerns. 

While old world fruit bats (Pteropodidae) have been pegged as the natural host for Nipah (and for its less well known Australian cousin Hendra), that family encompasses scores of species, and other types of bats may also be carriers. 

We also know that in addition to bats and humans - other mammals have been infected in the wild (horses, pigs, and dogs) - and many others have been experimentally infected in the lab (including guinea pigs, hamsters, ferrets, squirrel monkeys, and African green monkeys).

For an excellent, and fairly recent review of Nipah and Hendra, I can heartily recommend the JCM mini-review Nipah Virus Infection by Brenda S. P. Ang, Tchoyoson C. C. Lim, Linfa Wang.

Today, however, we have a study - published this week in PLoS Neglected Tropical Diseases - that uses machine learning to try to narrow down the field of bat species with the potential to host Nipah virus in India.

You'll find a some excerpts from a press release from the Cary Institute of Ecosystem Studies, followed by excerpts from and a link to the full open-access study.

Model predicts bat species with the potential to spread deadly Nipah virus in India 

Findings can help guide surveillance and prevent deadly outbreaks

Cary Institute of Ecosystem Studies

(EXCERPT)
      
India is home to an estimated 113 bat species. Just 31 of these species have been sampled for Nipah virus, with 11 found to have antibodies that signal host potential. Plowright notes, “Given the role bats play in transmitting viruses infectious to people, investment in understanding these animals has been low. The last comprehensive and systematic taxonomic study on the bats in India was conducted more than a century ago.”

Machine leaning, a form of artificial intelligence, was used to flag bat species with the potential to harbor Nipah. Han explains, “By looking at the traits of bat species known to carry Nipah globally, our model was able to make predictions about additional bat species residing in India with the potential to carry the virus and transmit it to people. These bats are currently not on the public health radar and are worthy of additional study.”

(Continue . . . )

Prioritizing surveillance of Nipah virus in India

Raina K. Plowright, Daniel J. Becker, Daniel E. Crowley, Alex D. Washburne, Tao Huang, P. O. Nameer, Emily S. Gurley, Barbara A. Han

Published: June 27, 2019
https://doi.org/10.1371/journal.pntd.0007393

Abstract

The 2018 outbreak of Nipah virus in Kerala, India, highlights the need for global surveillance of henipaviruses in bats, which are the reservoir hosts for this and other viruses. Nipah virus, an emerging paramyxovirus in the genus Henipavirus, causes severe disease and stuttering chains of transmission in humans and is considered a potential pandemic threat.

In May 2018, an outbreak of Nipah virus began in Kerala, > 1800 km from the sites of previous outbreaks in eastern India in 2001 and 2007. Twenty-three people were infected and 21 people died (16 deaths and 18 cases were laboratory confirmed). Initial surveillance focused on insectivorous bats (Megaderma spasma), whereas follow-up surveys within Kerala found evidence of Nipah virus in fruit bats (Pteropus medius). P. medius is the confirmed host in Bangladesh and is now a confirmed host in India. 

However, other bat species may also serve as reservoir hosts of henipaviruses. To inform surveillance of Nipah virus in bats, we reviewed and analyzed the published records of Nipah virus surveillance globally. We applied a trait-based machine learning approach to a subset of species that occur in Asia, Australia, and Oceana. In addition to seven species in Kerala that were previously identified as Nipah virus seropositive, we identified at least four bat species that, on the basis of trait similarity with known Nipah virus-seropositive species, have a relatively high likelihood of exposure to Nipah or Nipah-like viruses in India. 

These machine-learning approaches provide the first step in the sequence of studies required to assess the risk of Nipah virus spillover in India. Nipah virus surveillance not only within Kerala but also elsewhere in India would benefit from a research pipeline that included surveys of known and predicted reservoirs for serological evidence of past infection with Nipah virus (or cross reacting henipaviruses). Serosurveys should then be followed by longitudinal spatial and temporal studies to detect shedding and isolate virus from species with evidence of infection. Ecological studies will then be required to understand the dynamics governing prevalence and shedding in bats and the contacts that could pose a risk to public health.

(SNIP)

In addition to sampling bat reservoir hosts, sampling plans should consider that henipaviruses could be maintained in domestic recipient hosts. These hosts, with closer and more frequent contact with humans, can become bridge hosts for human infections [36].

For example, Nipah virus was repeatedly introduced into intensive commercial pig populations in Malaysia. These repeated introductions of Nipah virus into pig farms allowed accumulation of herd immunity and the conditions for long term persistence and regional spread that facilitated transmission to humans [10].

To narrow potential spillover pathways to humans in India, studies should consider susceptible domestic animal species with husbandry that facilitates virus persistence (e.g., intensive commercial farming systems with high turnover of animals).

Projecting the risk of Nipah virus outbreaks in humans requires identification of the reservoir hosts and the dynamics of Nipah virus within those hosts. Our predictions inform initial sampling that can be followed by a sequence of studies that investigate the bat species highlighted here. The machine learning approaches presented here can be the first step in a research pipeline to eventually understand the mechanisms underpinning epidemiologically important cross-species contacts.

(Continue . . . )

The past couple of decades have been an excellent time to be a Chiropterist, as the number of bat borne disease threats continue to mount.  A few (non-Nipah) examples include:

Potential For Zoonotic Emergence Of Coronavirus In Latin America

Nature: Fatal Swine Acute Diarrhoea Syndrome Caused By An HKU2-related Coronavirus Of Bat Origin

Emerg. Microbes & Infect.: Novel Coronaviruses In Least Horseshoe Bats In Southwestern China

PNAS: SARS-like WIV1-CoV Poised For Human Emergence

Sci Rpts: Avian & Human Influenza Compatible Receptor Cells In Little Brown Bats

Pennsylvania Ag Dept.: New Rules For Swine Exhibits Due to ASF Threat

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Every summer and fall for roughly the last decade American county and state fairs have had to deal with swine flu - a disease which can sometimes jump from pigs to humans (see Biosafety At The Fair This Summer) - and have even had to cancel some swine exhibits.

Although that threat continues, this year another porcine disease - one that does not infect humans - is on the horizon; African Swine Fever (ASF). 

While ASF has never been reported in North America, concerns over its eventual arrival are running high enough that the State of Pennsylvania has ordered new, far more stringent rules for exhibition swine at all venues (see letter below).

Letter to Fair Board Members, 4-H Leaders, and FFA Advisors

The result is that while properly vetted pigs can still be exhibited, all market swine exhibited must be moved directly to slaughter following the exhibition, and breeding hogs and market hogs cannot be on site at the same time (see 2019 Exhibition Swine Quarantine Order FAQs).

Between the logistics of complying with the new rules, and extra costs involved, some venues have decided to cancel swine exhibits entirely. 

These new rules, and their impacts, are a obviously a bitter pill to hundreds of 4-H and FFA exhibitors who spend most of the year getting ready for their local fair, and a disappointment to thousands of fair goers.

The PennState Extension Office has published a long article (excerpts below) on why these extra precautions have been put in place, and the costs to the industry should ASF begin to spread in the United States.

Swine Exhibitions in Pennsylvania 

Swine exhibition requirements in Pennsylvania have changed for 2019 as a precautionary measure of biosecurity due to current global movement of African Swine Fever (ASF). Let's talk about why this disease is a big deal.

Updated: June 17, 2019

(Excerpt)

Agree or disagree with the order placed on swine exhibitions this summer, this may be the first time that you are really wondering what ASF is, or why it is getting so much attention. This disease commands attention for 3 main reasons:

1. It is an exceptionally hardy virus, allowing it to survive in a wide variety of environments for exceptionally long periods of time (weeks to years).
2. There is no vaccine for this disease. If it gets into your herd, the response is 90-100% mortality from infection or herd depopulation before that point.
3. ASF is a global reportable disease that will stop trade agreements. In the U.S., pork exports make up 25% of all pigs produced in the U.S. If ASF gets into the U.S. and can’t be controlled, the price of all hogs will collapse, and likely take down other livestock commodities with it, like poultry or beef.

These reasons essentially amount to: if it gets in, it will be very hard to get out, and there will be a large financial cost in both loss of livestock and control needed to eradicate this virus.

In Pennsylvania, in addition to the cost of efforts to eliminate the virus, this could also look like the loss of over 2,300 jobs due to the loss of exports alone, and a threat to more than 11,000 jobs as the price of pork plummets. These numbers only reflect the losses from pig and pork production in PA, not counting economic hardships predicted to be observed in other livestock sectors or across the nation.

This virus would impact all pig producers in all markets: commodity, show, local, or specialty markets. The price of pork would drop dramatically, and that drop will likely drag down the price of beef and poultry as well as consumers move to purchase cheaper products. 

(Continue . . . )

Six weeks ago, in USDA Enhances Domestic ASF Surveillance Efforts, we looked at plans for enhanced testing and surveillance for ASF in American pigs, in hopes of detecting - and stamping out - any infections as early as possible.

The USDA also recently released a 28-page ASF response plan, in the event  the virus turns up on American soil. 

While none of this means that the importation of ASF to North America is inevitable, there are legitimate reasons for concern. 

In 2013 we saw the arrival of another, far less dangerous porcine virus - PEDV  - which is believed to have originated from China (see mBio: PEDV - Porcine Epidemic Diarrhea Virus – An Emerging Coronavirus).

While Pennsylvania appears to have enacted the most aggressive rules (so far), other states are undoubtedly considering their own measures, and when to implement them.

Meanwhile, ASF continues to spread in Eastern Europe, Russia, China, and Asia, and threatens to expand it reach.  A few past blogs on its progress include:

DEFRA: ASF Outbreak Assessment #21 - Eastern Europe

OIE: ASF Arrives In Laos & FAO Update

African Swine Fever In China: Epizootic or An EpicZootic?

Japan MAFF: 28th Farm Outbreak Of Classical Swine Fever

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Classical Swine Fever re-emerged in Japan last September after an absence of 26 years, and while it took 164 days for Japan to report their first 10 farm outbreaks, we've seen that pace quicken since March, with 18 farm outbreaks reported over the past 115 days. 

The OIE has also reported a tripling in the number of infected wild boar (rising from 218 in March to 655 in their last report) detected in Gifu and Aichi Prefectures.

CSF, while similar in appearance and impact to African Swine Fever (ASF) - which is currently spreading in China and much of Asia - is caused by a different virus. 

Both are highly contagious among pigs, and can be economically devastating for pork producers, but neither disease poses a direct human health threat.

Today's (translated) announcement from Japan's MAFF confirms only one new outbreak, but testing and investigations are ongoing at adjacent farms, meaning additional announcements could be forthcoming.

Confirmation of suspected affected animals of swine fever in Aichi Prefecture, about (28 case was in Japan)

Ryowa first year June 29,
the Ministry of Agriculture, Forestry and Fisheries

Today, suspected affected animals of swine fever has been confirmed in a farm in Nishio, Aichi.

We are taken all possible measures for the quarantine measures for the disease.

Interview in the field, thank you for your cooperation as strictly refrain from such that there is a risk that cause the spread of the disease.

1. Overview of the occurrence farm

Location: Nishio, Aichi
breeding situation: 1,014 head

2. Background

(1) Aichi Prefecture, June 28 (Friday), from the farm, received a report of a breeding pig has exhibited abnormal, we conducted a site inspection by animal health inspectors.
(2) the same day, because the suspicion of swine fever is caused by the inspection at the Livestock Hygiene Service Center, was subjected to a thorough examination, today (June 29, Saturday), turned out to be a suspected affected animals of swine fever want did.
(3) Therefore, 3 together with the quarantine measures for feeding pigs of the farm, adjacent to the farm, feces, compost carrier vehicle was moving pig from 3 farms and their farms used jointly breeding pig farm is also a suspected affected animals of swine fever, it will take quarantine measures (suspected affected animals total: 7,565 horses (4 units 7 farm)).

3. of future correspondence

On the basis of the "specific livestock epidemic quarantine guidelines for classical swine fever", and taken all possible measures for the following quarantine measures, and the like.

(1) The farm breeding pigs slaughtered and baked burial, and carried quickly and accurately quarantine measures necessary for setting of the movement restriction zone.
(2) for the farm of movement restricted area, it will be carried out as soon as possible occurrence status check inspection.
(3) Since the spread of infection prevention, strengthening the disinfection of peripheral generation farm, we set up a disinfection point to the main road.
(4) for the investigation of such infection route, and dispatch the epidemiological investigation team of the country.
(5) aims to ensure the early detection and early notification of the disease.
(6) strive to relevant ministries and sufficient cooperation, producer, consumer, we will endeavor to provide accurate information to the distributors and the like.
(7) thorough guidance on compliance with the Standards of Rearing Hygiene Management of intrusion prevention, etc. to the farm disinfection and wild animals of the farm.
(8) In order to investigate and prevent the spread of such infection route, it will assume all the possibilities investigation.

                (Continue . . . )


As of May, 2019 the OIE lists the following 36 nations as being free from Classical Swine Fever.

CSF free Members

According to Resolution No. 22 (87th General Session of World Assembly, May 2019)

Members recognised as free from CSF according to the provisions of Chapter 15.2. of the Terrestrial Code :

Hong Kong Reports 6th Human Infection With Rat Hepatitis E Virus

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Last fall Hong Kong recorded the first known human infection with a rat Hepatitis E virus (see ECDC CDTR Notice) in an elderly immunosuppressed individual who had recently received a liver transplant.

The announcement from HKU reads, in part:

HKU discovers that rat hepatitis E virus can cause hepatitis in humans

28 Sep 2018

Rat hepatitis E virus (rat HEV) was first discovered in 2010 and circulates in house rats (Rattus rattus) and sewer rats (Rattus norvegicus). It is very distantly related to human hepatitis E virus variants. Human infection by rat HEV has never been documented previously. A study led by Professor Yuen Kwok-Yung, Henry Fok Professor in Infectious Diseases, Chair Professor of Infectious Diseases, and Dr Siddharth Sridhar, Clinical Assistant Professor at the Department of Microbiology of Li Ka Shing Faculty of Medicine, The University of Hong Kong (HKU) has discovered for the first time that rat HEV can infect humans.

Findings of the study

While investigating the impact of hepatitis E infection among immunocompromised transplant recipients in Hong Kong, the researchers identified a 56-year-old man who was taking immunosuppressive drugs after deceased-donor liver transplantation. He presented with persistently abnormal liver function tests indicating dysfunction of the liver graft. Rat HEV was identified in several of his clinical samples including stool, blood, and liver tissue. Complete genome sequencing of the virus isolate showed that it was closely related to a rat HEV strain previously identified in Vietnam.

Epidemiological investigation could not find any evidence of rat HEV infection in the organ donor or blood product donors excluding these individuals as sources of infection. However, evidence of rodent infestation was noted in the patient’s housing estate. Rat HEV could not be detected in rodent fecal samples collected from the housing estate, but screening of archived rodent samples from the patient’s residential district shows that rat HEV circulates in rats in Hong Kong. The patient was given oral ribavirin, an effective antiviral for chronic hepatitis E infections, and the infection has been cured. His liver function has returned to normal.

        (Continue . . . )


Retrospective testing uncovered a 2nd case, involving a 70-year old woman in November of last year (cite), and since then three more cases have been announced by Hong Kong's CHP.

In a letter to doctors last month, the CHP wrote:

Since November 2018, the Public Health Laboratory Services Branch
(PHLSB) of CHP has enhanced the surveillance of both human and rat HEV. In May 2019, PHLSB detected three additional cases of human rat HEV infection involving three men aged 67, 74 and 81 years respectively. 

All three cases had major underlying illnesses (one with metastatic carcinoma, and two had renal transplants and were on immunosuppressants) and presented with liver function derangement without other obvious symptoms of acute hepatitis

Today, the CHP announces a 6th human infection.

HP investigates case of human infection of rat Hepatitis E virus

The Centre for Health Protection (CHP) of the Department of Health is today (June 28) investigating a case of human infection of rat Hepatitis E virus (HEV) and urged members of the public to be vigilant against hepatitis E infection and to strictly observe good personal, food and environmental hygiene.

The case involves a 73-year-old man with underlying illnesses, who had presented with liver function derangement earlier this month. He has been in a stable condition all along and no hospitalisation is required. His blood sample tested positive for rat HEV upon laboratory testing.

The CHP's epidemiological investigations revealed that the patient resided in Wong Tai Sin. He could neither recall having direct contact with rodents or their excreta, nor had noticed rodents in his residence. He had no travel history during the incubation period.

"Based on the available epidemiological information, the source and the route of infection could not be determined. The CHP's investigation is ongoing," a spokesman for the CHP said.

"The CHP has already informed the Pest Control Advisory Section of the Food and Environmental Hygiene Department about the case to carry out rodent control measures and survey as appropriate," the spokesman added.

The exact mode of transmission of rat HEV to humans is unknown at the moment. Possible routes of transmission include ingestion of food or water contaminated by rodents or their excreta, exposure to environments or objects contaminated by rodents or their excreta and direct contact with rodents or their excreta. The usual HEV causing human infection is transmitted mainly through the faecal-oral route.

(Continue . . . )

Earlier this year a case was reported in Canada, detected in a person with recent travel history to Africa (see Rat hepatitis E may be ‘under-recognized’ cause of hepatitis infection), but it remains unknown how widespread transmission really is.

Hong Kong has a notorious`rat problem', and following last month's announcement of 3 additional Rat Hepatitis E cases, HK's Food and Health Bureau announced a massive cleanup campaign. 

On June 20th, they issued their first progress report:

Government reviews territory-wide cleansing and anti-rodent work (with photos)

The interdepartmental Pest Control Steering Committee met today (June 20) to review the enhanced anti-rodent work carried out by various government departments since the cleaning campaign over the territory commenced on May 20 and set priorities for the work ahead.
The Government has provided an additional funding of $91 million this financial year to various departments for enhancing pest control work. During today's meeting, various departments discussed the extra resources required for the relevant work. The Government had earlier expressed that full support would be given to department’s pest prevention and control work.

Various departments briefed the meeting on the progress of territory-wide cleaning work in all 18 districts. They include:

- District Offices (DO) of the Home Affairs Department (HAD) have assisted different departments on reporting the cleaning and anti-rodent work carried out in each district as well as the liaison with stakeholders in the community to raise public awareness of rodent prevention and control.

- Among the some 180 public rental housing estates in the territory, the Housing Authority (HA) has examined the rodent-proofing structure installed in 133 estates. The HA will repair and arrange the reinforcement of the existing structure as well as install additional structure immediately if needed with a view to eliminating activities of rodents and their harbourage points. The HA has also enhanced the cleaning work in all public rental housing estates and strengthened enforcement action under the Marking Scheme.

(Continue . . . )

Whether human infections with rat hepatitis E are a recent phenomenon, or have simply been under-recognized, is less than clear. Now that it is on our radar, however, we should get a clearer picture of its true incidence and impact.

NHS: Update On Mid Essex Streptococcus Outbreak

Essex County - Credit Wikipedia

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On Tuesday, in UK: Essex NHS Reports Outbreak Of Invasive Group A Streptococcus - 12 deaths, we looked at reports of an unusual cluster of iGAS (Invasive Group A Streptococcus) cases in Essex County, in the South-east of the United Kingdom.  

While a definitive cause of this outbreak has yet to be established, the NHS is taking steps to prevent potential transmission via asymptomatic carriers, and is working to improve hand hygiene and the use of PPEs by local nurses.

According to the latest statement, the NHS is giving nursing staff who treat patients with chronic wounds antibiotic prophylaxis, has conducted a deep cleaning of community nurse bases, and is restricting Braintree district nurse teams from working outside out their postcode.

The ability of asymptomatic carriers to spread Strep A is only poorly understood, but the CDC states:

Carriage

Asymptomatic group A strep carriers usually do not require treatment. Carriers have positive throat cultures or are RADT positive, but do not have clinical symptoms or an immunologic response to group A strep antigens on laboratory testing.

Compared to people with symptomatic pharyngitis, carriers are much less likely to transmit group A strep to others. Carriers are also very unlikely to develop suppurative or nonsuppurative complications.

The full statement from the Mid Essex NHS follows, after which I'll have a bit more:

Mid Essex streptococcus outbreak – statement by Dr Anna Davey, CCG Chair, at Board today

At the CCG's Board meeting in public held at Spring Lodge Community Centre in Witham this afternoon (Thursday 27 June), our Chair, Dr Anna Davey, gave the following update on the invasive Group A Streptococcus (iGAS) outbreak in mid Essex.

I want to give you all an update on the ongoing incident here in mid Essex. Twelve people have sadly died and I want to start by expressing our sincere condolences to their families.

We have established an incident management team and are working hard with colleagues from Public Health England, Provide Community Interest Company, who provide the majority of our out of hospital services, NHS England and NHS Improvement, to understand why this has happened and to prevent any more cases from occurring.

There have been 32 cases of iGAS in Essex. Those affected are elderly people in Braintree District, Chelmsford City and Maldon District. The vast majority of patients were receiving treatment for wounds, some in care homes but most in their own homes. A single case was found in Basildon in 2018 and a single case in Southend in February 2019. There does not appear to be a direct link between the cases in south Essex and mid Essex.

To give you a brief overview, Group A streptococcus, or GAS bacteria, can be found in the throat and on the skin and will not cause any illness for most people. Most Group A streptococcus infections can cause mild illnesses such as a sore throat, also known as strep throat, scarlet fever or a skin infection. For most healthy people this will cause no more than a mild illness.

On rare occasions, this bacteria can enter the body and cause severe, and sometimes life-threatening conditions. This is called Invasive Group A Streptococcal disease – iGAS. While this infection is rare, it is not new and has been seen in the UK before.

We have put in place measures to prevent the spread of this infection, including giving all community nursing staff who treat patients with chronic wounds antibiotic prophylaxis.

A deep cleaning of all community nurse bases has been conducted on all premises and to ensure the infection does not spread out of the locality, district nurse teams working within the CM7 Braintree area are only working within this postcode for the time being. This is because the majority of cases have been within this area.

We are taking wound swabs from all patients who are being treated for wounds in the area to check for the bacteria, and increasing opportunities for hand hygiene and use of personal protective equipment among staff.

We understand this is a worrying time for people, and know how frustrating it is that we don’t have answers to lots of the questions you may have. But we want to reassure members of the public that the risk of contracting iGAS is very low for most people. Treatment with antibiotics is very effective if started early.

We are continuing to work with Public Health England to stop the spread of this outbreak and ensure our local community is protected.

Our Freephone helpline number, 03000 032124, is open Monday to Friday, 9am to 5pm, for anyone with concerns about iGAS infection.We will also continue to keep our website updated as and when we have more information on the outbreak or investigation.

For a more complete look at the knowns and unknowns of asymptomatic carriage of Strep A, you may wish to review the following article published in 2014.

The Group A Streptococcal Carrier State Reviewed: Still an Enigma

Gregory P. DeMuri Ellen R. Wald

Journal of the Pediatric Infectious Diseases Society, Volume 3, Issue 4, December 2014, Pages 336–342, https://doi.org/10.1093/jpids/piu030
Abstract

Despite the common nature of group A streptococcal (GAS) infections, the carrier state of this organism is not well understood. In this article, we review the historical and recent research on the definition, epidemiology, and pathogenesis of the GAS carrier state. In addition, we outline trials of antimicrobial agents in the eradication of the carrier state and discuss indications for providing treatment to patients in the clinical setting.

        (SNIP)

CONCLUSIONS

Despite decades of research, the GAS carrier state remains poorly understood. A working definition used in some clinical trials and practical to clinicians is the patient who harbors GAS in the pharynx after adherence to an appropriate antibiotic for an episode of pharyngitis presumed to be caused by GAS.

Streptococcal carriers are common in school-age populations, representing 10%–15% of children in most surveys. Carriers have little risk for nonsuppurative complications of GAS and though they may possibly transmit the organism to others, the degree of communicability is less than from acutely infected individuals. Most children who are carriers do not require treatment, but an attempt at eradication of the carrier state may be of benefit in select children.
 

MMWR: More Tales From The Crypto

Photo Credit CDC PHIL



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Several times over past few years we've looked at water and food borne illness outbreaks due to parasites - both in the United States and around the world - involving cyclospora & cryptosporidium. 

CDC HAN: Increased Cyclospora Infection, United States, Summer 2017

MMWR: Cyclosporiasis Outbreak Summer 2013

Eurosurveillance: More Tales From The Crypto

UK: Return To The Crypto

While Cyclosporiasis has been making inroads and headlines the past few years, Cryptosporidiosis still leads the pack, with an EID study published in early 2011 estimating 750,000 Crypto infections in the U.S. each year (see Foodborne Illness Acquired in the United States—Major Pathogens), although only about 8,000 are laboratory confirmed. 

Cryptosporidium is an extremely chlorine-tolerant parasite, making it particularly difficult to eliminate from swimming pools, fountains, and public water sources.   

Occasionally campers, swimmers, or those drawing water from untreated wells will contract Crypto, but the largest outbreak occurred in Milwaukee in 1993, when Cryptosporidium entered the public water supply (exactly how, remains a mystery), and sickened 400,000 people and killed more than 100 who were immunocompromised.

The Milwaukee incident has led to increased water testing, and the use of ozone, filters, and other interventions across the nation to help make our water supply safer.

Despite these improvements, the CDC reports a steady increase in Crypto cases over the past decade.  Yesterday's MMWR carried a report on 444 outbreaks reported over the past decade.

First the CDC's press release, and then a link to the full MMWR report.

CDC Press Release: Outbreaks of diarrhea caused by summertime parasite increased from 2009 through 2017

Pools, cattle, and childcare settings continue to be important sources of Crypto outbreaks

Press Release

Embargoed Until: Thursday, June 27, 2019, 1:00 p.m. ET
Contact: Media Relations (404) 639-3286

Outbreaks of Cryptosporidium (Crypto) in the United States increased an average 13% each year from 2009-2017, according to a report published in CDC’s Morbidity and Mortality Weekly Report.

Crypto, a parasite, is spread through the poop of infected humans or animals. People can get sick after they swallow the parasite in contaminated water or food or after contact with infected people or animals. Crypto is the leading cause of disease outbreaks in the United States linked to water, specifically outbreaks linked to pools or water playgrounds.

Hundreds of outbreaks caused by Crypto

The report describes 444 outbreaks reported from 2009 through 2017, resulting in 7,465 people becoming sick, 287 hospitalizations, and one death.

• 35% of the outbreaks were linked to treated swimming water in places like pools and water playgrounds.
• 15% were linked to contact with cattle, particularly calves who were still nursing.
• 13% were linked to contact with infected people in childcare settings.
• 3% were linked to drinking raw (unpasteurized) milk or apple cider.

Improvements in testing patients for Crypto in recent years might be contributing to increased detection of outbreaks.

Michele Hlavsa, R.N., M.P.H., chief of CDC’s Healthy Swimming Program

“Young children can get seriously sick and easily spread Crypto. They don’t know how to use the toilet and wash their hands, or are just learning how. But we as parents can take steps to help keep our kids healthy in the water, around animals, and in childcare.”

Crypto is a challenging parasite

Crypto is protected by an outer shell that makes it tough to kill. For example, it can survive for days in chlorinated water in pools and water playgrounds or on surfaces disinfected with chlorine bleach. Crypto can easily cause outbreaks because it only takes a few germs to make someone sick, and there can be millions of Crypto germs in poop. Someone sick with Crypto can have diarrhea for up to three weeks.

Protect yourself and family from getting sick

Outbreaks caused by Crypto occur most commonly in the summer. Follow these effective steps to protect yourself and others this summer and year-round:

• Do not swim or let kids swim if they have diarrhea.
• If diagnosed with cryptosporidiosis, do not swim until two weeks after diarrhea completely stops.
• Do not swallow the water you swim in.
• Keep kids sick with diarrhea at home and away from childcare.
• Wash your hands with soap and water after coming in contact with animals or anything in their environment, especially animal poop. Alcohol-based hand sanitizers do not work effectively on Crypto.
• Remove shoes worn in the animal environments (for example, in barns) before going inside your home.
• If you drink milk or apple cider, only buy if it has been pasteurized.

National surveillance system can help detect outbreaks

CryptoNet is the first U.S. national tracking system for a parasitic disease that is based on DNA fingerprinting. Crypto DNA fingerprinting can help determine how the parasite spreads and help detect and investigate outbreaks.

For more information on Crypto, visit https://www.cdc.gov/parasites/crypto/gen_info/prevention-general-public.html.

Excerpts from yesterday's MMWR report are below. Follow the link to read it in its entirety.

Cryptosporidiosis Outbreaks — United States, 2009–2017

Weekly / June 28, 2019 / 68(25);568–572

Radhika Gharpure, DVM1,2; Ariana Perez, MPH1,3; Allison D. Miller, MPH1,4; Mary E. Wikswo, MPH5; Rachel Silver, MPH1,3; Michele C. Hlavsa, MPH1

Summary

What is already known about this topic?

Cryptosporidium is the leading cause of outbreaks of diarrhea linked to water and the third leading cause of diarrhea associated with animal contact in the United States.

What is added by this report?

During 2009–2017, 444 cryptosporidiosis outbreaks, resulting in 7,465 cases were reported by 40 states and Puerto Rico. The number of reported outbreaks has increased an average of approximately 13% per year. Leading causes include swallowing contaminated water in pools or water playgrounds, contact with infected cattle, and contact with infected persons in child care settings.

What are the implications for public health practice?

To prevent cryptosporidiosis outbreaks, CDC recommends not swimming or attending child care if ill with diarrhea and recommends hand washing after contact with animals.

Cryptosporidium is a parasite that causes cryptosporidiosis, a profuse, watery diarrhea that can last up to 3 weeks in immunocompetent patients and can lead to life-threatening malnutrition and wasting in immunocompromised patients.* 

Fecal-oral transmission can occur by ingestion of contaminated recreational water, drinking water, or food, or through contact with infected persons or animals. 

For the period 2009–2017, public health officials from 40 states and Puerto Rico voluntarily reported 444 cryptosporidiosis outbreaks resulting in 7,465 cases. Exposure to treated recreational water (e.g., in pools and water playgrounds) was associated with 156 (35.1%) outbreaks resulting in 4,232 (56.7%) cases.

Other predominant outbreak exposures included contact with cattle (65 outbreaks; 14.6%) and contact with infected persons in child care settings (57; 12.8%). The annual number of reported cryptosporidiosis outbreaks overall increased an average of approximately 13% per year over time. 

Reversing this trend will require dissemination of prevention messages to discourage swimming or attending child care while ill with diarrhea and encourage hand washing after contact with animals. Prevention and control measures can be optimized by improving understanding of Cryptosporidium transmission through regular analysis of systematically collected epidemiologic and molecular characterization data.

(Continue . . . )

To learn more about Crypto, the CDC maintains a large Crypto Information Site.