Are Dangerous Viruses Just Horsing Around? Neigh...

--Google Images

The recent Kentucky Derby featured superbly athletic horses at the prime of their lives. Unfortunately, not all horses (or other livestock for that matter) are so fortunate. In the past week, 2 stories have been hoofing around the news. The first has been an outbreak of vesicular stomatitis virus, a rhabdovirus like the infamous rabies. It primarily infects insects and livestock, but it can be a zoonotic disease of humans that consists of flu-like symptoms. VSV has also been studied as a candidate for virus-based vaccine therapy (http://wwwnc.cdc.gov/eid/article/21/2/14-1649_article).

            In Kane County, Utah, several horses and a mule have become sick with VSV. While many animals recover from vesicular stomatitis, it can cause lesions in the animals’ mouths and on their hooves that cause them pain. It also causes them to show a severe decrease in appetite, which is especially problematic for dairy cows and other animals who are supposed to grow fast and/or be in good physical condition. While the exact means of transmission isn’t known, it is thought that saliva and fluid from ruptured blisters are a likely mechanism. Seeing as rabies is also transmitted via saliva, this seems plausible.

--Vesicular Stomatitis Virus, from Wikimedia Commons

            In Oregon, four horses have tested positive for equine herpes virus (EHV-1). Herpesviridae, as we’ve learned, is a very old and successful group of viruses that infect a myriad of different species. These viruses can cause a wide variety of symptoms (remember the 9 human herpes viruses?).

--EHV-1, from http://www2.ca.uky.edu/

 Like all herpesviruses, it can go latent and then reactivate to cause clinical disease. Horses infected with EHV-1 can suffer from respiratory and neurologic symptoms (e.g. loss of muscle tone), as well as fever, urine dribbling and nasal discharge. In severe cases, the animal may die, or a pregnant mare may abort her fetus. The symptoms are treatable, but as is the case with human herpes viruses, “unlike love, herpes is 4ever”™. While humans aren’t in any danger from the virus, they can spread it on their clothing and equipment.

--Joe

http://www.ksl.com/?nid=148&sid=34526457

http://www.aphis.usda.gov/publications/animal_health/content/printable_version/fs_vesicular_stomatitis_2012.pdf

http://www.ktvz.com/news/equine-virus-now-detected-in-four-oregon-horses/32804444

Sexual Transmission as a Possible Route of Infection for Ebola

More evidence of sex as a possible mode of transmission for the Ebola virus recently emerged out of Liberia this week.  A Liberian woman contracted the virus in March despite having no contact with deceased Ebola victims or those displaying Ebola-like symptoms, and no travel history to countries where Ebola is currently active.  However, this woman did have unprotected vaginal intercourse with an Ebola survivor a week before she developed symptoms, leading investigators to suspect sex as the mode of transmission.

Sexual transmission of the virus has long been suspected, as the virus has been found to linger in the sperm of men for up to 101 days after development of symptoms.   However, if sexual transmission is indeed the route of transmission in this case, it may indicate that the virus can persist for much longer in the sperm; the man developed symptoms 199 days - more than 6 months - before having sex with the woman.

It should be noted, however, that another woman who had sex with this man between February and March did not contract the disease.  Furthermore, there was no mention that the virus was actually found in the survivor's sperm.  As a result, it is possible that the virus was not contracted sexually, particularly because the screening process for risk factors relies the investigators asking the right questions, and the respondent recounting his or her experiences accurately.

The CDC currently recommends the use of condoms when having sex and avoidance of coming into contact with the semen of a male survivor to prevent sexual transmission of Ebola.

--Andrew Duong

http://www.npr.org/blogs/goatsandsoda/2015/05/01/403600464/a-man-said-to-be-ebola-free-could-still-infect-a-partner-during-sex?utm_medium=RSS&utm_campaign=storiesfromnpr

http://www.cdc.gov/vhf/ebola/about.html

Parvovirus Plaguing Pups

Cornwall, Ontario is not a good place for dogs right now.

Since 2014, the region has seen an usual uptick in cases of canine parvovirus--a virus of the same family that includes human B19 virus, notable for 5ths disease it causes in humans. However, in dogs it can have even deadlier effects, often leading to death, especially in young pups.  In this population it can attack the heart.

Canine parvovirus is very persistent and can be spread by direct contact between dogs, but also via surfaces that the animal comes into contact with such as bowls or leashes. When infected, if the dog does not receive supportive care, the mortality rate of the virus can exceed 90%.

While a vaccination against canine parvovirus does exist, most dogs do not get vaccinated until 8 weeks or later, leading to a window of possible infectivity that can be deadly. It also doesn't help that the vaccination is fairly expensive--around $300 for the full series.

Hello Mr. Noro!

Holland American passengers are feeling a little green, and it's not just from sea sickness.
Friday, the popular, upscale cruise line had to remove both passengers and crew after a raging case of Norovirus ran through the ship, sicking over 60 passengers and 11 crew--approximately a full 4% of the people on board.

The ship was supposed to be blithely sailing the Caribbean, but the unexpected passenger had other plans. Spread via a fecal-oral route, where virus from infected individuals is left on surfaces to be picked up and ingested by unsuspecting victims.  Norovirus is a particularly explosive and unpleasant combination of vomiting, nausea and diarrhea.

According to the company, the entire ship was disinfected and should be ready to sail again soon.

--Lauren
http://miami.cbslocal.com/2015/05/01/crews-passengers-taken-off-ship-over-virus/

Using non-invasive technologies to detect HIV reservoirs

New research suggests that a noninvasive technique called antibody-targeted positron emission tomography (immunoPET) can be used visualize HIV reservoirs more effectively than tissue biopsies, the currently employed method.  Identifying HIV reservoirs is important not only in understanding the disease, but also in creating targeted treatments that rid the virus in hard-to-detect areas.

In the context of HIV, the immunoPET technique tags specific antibodies with positron emitting radionuclides that react to gp120 - the envelope protein of HIV.  These tagged antibodies can later be observed on a screen and pinned to a specific location in the body.  In macaques, the immunoPET technique was able to identify where latent HIV resided in antiretroviral treated specimens. In contrast to tissue biopsies that may require samples from areas of the body that are hard or impossible to reach (e.g. gastrointestinal tract), the immunoPET can visualize the virus' location without any physical sample.  An additional benefit of the immunoPET technique is that it is an in vivo technique that is capable of revealing trends over time, for example, the path that HIV takes to establish reservoirs in certain areas of the body.

ImmunoPET is already used as in vivo method used in the diagnosis and prognosis of certain cancers and cardiovascular conditions.  However, it has not been used commonly in the field of infectious disease.  Such a technique is promising for a virus whose evasive mechanisms have eluded researchers for years.

--Andrew Duong
http://www.nature.com/nmeth/journal/v12/n5/full/nmeth.3373.html

Rubella Eliminated from the Americas: Good News Amidst Anti-Vaccine Hysteria

On April 29^th, 2015, the WHO announced that the Americas region (which comprises all of North/South America except for Greenland) was the first of the WHO-defined regions to completely eliminate rubella. Rubella is now that 3^rd vaccine-preventable infection to be eliminated from the United States (after smallpox and polio). While this news comes 5 years later than the original PAHO (Pan-American Health Organization)/WHO plan dictated, this is still a monumental feat. A once-common rash of childhood, rubella has been on the decline over the past 15 years because of the ubiquity of the MMR vaccine. Director General of the WHO Margaret Chan stated that a 3-year Vaccine Action Plan gave the elimination effort the last big push it needed. The last cases of endemic Rubella were reported in Argentina and Brazil in 2009. While rubella is generally not as dangerous as measles, congenital rubella can still cause miscarriage, deafness, blindness and other complications for developing fetuses.

Within the next 5 years, the WHO hopes to solidify a plan (with dates) for the global eradication of rubella and measles. Measles will likely be even more difficult to eradicate because measles is one of the most contagious viral infections known.

In the mean time, they advise parents to keep vaccinating their kids. Let’s hope the anti-vaxxers don’t mess this up.

http://www.upi.com/Health_News/2015/04/29/WHO-Americas-the-first-to-eliminate-rubella/2231430356042/ 

http://www.mayoclinic.org/diseases-conditions/rubella/basics/definition/con-20020067

http://www.who.int/immunization/newsroom/Measles_Rubella_StrategicPlan_2012_2020.pdf

http://www.paho.org/hq/index.php?option=com_content&view=article&id=10798%3Aamericas-free-of-rubella&Itemid=1926&lang=en

--Joe

Rubella Virus Eliminated from the Americas

Big news came out today regarding the state of the rubella virus: the Pan American Health Organization (alongside the CDC, UNICEF, and the United Nations Foundation) has now officially declared rubella eliminated from the Americas - the first WHO region in the world to have done so. Although the last endemic case occurred in 2009 in Argentina, the announcement was delayed to ensure that the virus was in fact eliminated since the virus can sometimes persist without being clinically apparent.

Rubella, otherwise known as German measles, is a disease associated with fetal death and congenital defects, including congenital heart failure.  In normal, healthy adults rubella rarely gives rise to serious complications; symptoms generally include a rash and fever.  However for mothers and their fetuses, the disease can be deadly.  To give some perspective, in the United States from 1964-1965, 11,000 fetuses died from factors related to maternal rubella infection, and 20,000 newborns were born with defects.

Rubella is primarily prevented through the administration of the MMRV vaccine, a vaccine that protects against measles, mumps, rubella, and varicella zoster (chicken pox).  While experts are optimistic about eliminating the virus in several WHO regions, including the Europe region, eradication of rubella from the world is still a long ways away, as the virus is expected to persist in other regions for some time.

--Andrew Duong

http://www.nytimes.com/2015/04/30/health/rubella-has-been-eliminated-from-the-americas-health-officials-say.html
http://time.com/3840211/americas-eliminate-rubella/