Mosquitoes and Ticks and Fleas, Oh My!

“Disease cases from mosquito, tick, and flea bites tripled in the US from 2004 to 2016,” according to the CDC, with over 640,000 cases reported. They are blunt in their assessment that the U.S. is currently ill prepared to deal with vector borne diseases. State and local health departments, which the CDC notes are critical in controlling these diseases, are chronically underfunded.

Dr. Lyle R. Petersen, the agency’s director of vector-borne diseases, says that “the numbers on some of these diseases have gone to astronomical levels,” and that “the real case numbers were undoubtedly far larger.” He explains there are several factors at play:

“Ticks thriving in regions previously too cold for them, and hot spells triggering outbreaks of mosquito-borne diseases. Other factors include expanded human travel, suburban reforestation and a dearth of new vaccines to stop outbreaks…A recent survey of mosquito control agencies found that 84 percent needed help with such basics as surveillance and testing for resistance to pesticides”

A handful of super fun tick-borne diseases: Lyme disease, Anaplasmosis, Babesiosis, Rocky Mountain Spotted Fever, Powassan virus, and Tularemia.

For the mosquito lovers, there’s Chikungunya, Dengue, Eastern equine encephalitis, West Nile virus, Yellow fever, Zika, and malaria.

As you should know from reading this blog, the best known disease caused by fleas: the Plague.

Can the Zika Virus Treat Brain Cancer?

The Zika virus, which rose to epidemic proportions in 2015, can cause devastating congenital brain abnormalities and has been linked to Guillain-Barré syndrome, a condition in which the immune system attacks the nerves and can result in paralysis. It’s transmitted by everyone’s favorite insects, mosquitoes. (Actually, my favorite insects are dead ones.) According to the CDC, many people will have no symptoms or very mild symptoms, but for pregnant woman, the danger of passing the virus onto the fetus is high. This has had heartbreaking consequences. In a study discussed in the NY Times:

But 15 children, eight girls and seven boys, had a range of symptoms, most of which had not improved since infancy. All had severely impaired motor skills, with all but one child meeting the conditions for a diagnosis of cerebral palsy. Most had seizures and sleeping problems. Eight had been hospitalized at some point, most for bronchitis or pneumonia. Nine had difficulty eating or swallowing, which can be life-threatening because food can get stuck in the lungs or the children can be malnourished.

However, it seems the very thing that allows the Zika virus to cause such devastation in babies may be the key to a new brain cancer treatment. A new study, published in the Journal of Experimental Medicine, showed that injecting the Zika virus in mice “shrank aggressive tumors… yet left other brain cells unscathed.”

Human trials are still a way off, but experts believe Zika virus could potentially be injected into the brain at the same time as surgery to remove life-threatening tumours…

Researcher Dr Michael Diamond said: “Once we add a few more changes, I think it’s going to be impossible for the virus to overcome them and cause disease.

“It looks like there’s a silver lining to Zika. This virus that targets cells that are very important for brain growth in babies, we could use that now to target growing tumours.”

Dengue Vaccine Gone Wrong?

A Dengue vaccine program was recently suspended in the Philippines due to concerns that the “vaccine could worsen the potentially deadly disease in people not previously infected.” The vaccine, known as Dengvaxia, has been given to over 830,000 children. It’s the first-ever approved dengue vaccine, produced by the French pharmaceutical company Sanofi. While it appears to be effective in people who have already had the virus, given the results of the study, the vaccine program has been suspended pending a review.

Dengue is an infection caused by mosquitoes. It’s a flu like illness found in tropical and sub-tropical climates and can be deadly. It’s the leading cause of serious illness and death among children in these areas. Infection rates have grown globally in recent decades and half the worlds’ population is at risk. Early detection and access to proper medical care dramatically lowers fatality rate.

Did a researcher foresee this problem?

Four decades ago, Dr. Scott Halstead, a leading figure in dengue research, first proposed that antibodies from an initial exposure to one of four types of the disease could increase the risk of a potentially lethal complication called severe dengue when a person was infected a second time, a process know as antibody-dependent enhancement or ADE.

This phenomenon could make development of a dengue vaccine tricky.

Rather than being protective, a shot given to someone who had never had dengue could act like a first infection, increasing their risk of severe dengue when they were exposed a second time.