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Saturday, November 29, 2014

University of Pennsylvania study suggests bedbugs can transmit Chagas disease

Disclaimer: At this time there have been no proven cases of bedbugs transmitting Chagas

Researchers have known about Chagas disease for over a century, but a recent study may have identified a new carrier of the deadly disease which poses a unique risk for humans. Chagas is a parasitic disease which attacks major organs and is responsible for approximately 50,000 deaths each year, mostly in Mexico, South and Central America. Now, a report published Nov. 17, 2014 in the American Journal ofTropical Medicine and Hygiene indicates that the disease, which is also known as American Sleeping Sickness, may potentially have a new form of transmission via bedbugs (Cimex Lectularius).

The study is a result of a joint project between the University of Pennsylvania and a major medical school in Peru, Universidad Peruana Cayetano Heredia. The study looked at the possibility of Chagas disease being acquired by bedbugs through contact with mice. Prior to the study, researchers had believed that Chagas was only transmittable through the fecal matter of its primary vector, commonly referred to as the “Kissing Bug”. This new research proves that just like the kissing bug, bedbugs can also transmit the protozoan parasite through its feces. Trypanosoma cruzi, or T. cruzi as it is more frequently called, is the parasite which actually causes Chagas disease.

6 life stages of Triatomine-"Kissing Bug"
Photo courtesy of  Thierry Heger

About Chagas disease

Chagas disease gets its name from its discoverer, Dr. Carlos Chagas, who first discovered the disease back in 1909. Chagas was a Brazilian scientist, clinician and researcher with a field of practice primarily focused on improving sanitary conditions and studying bacteria. For most of his life Dr. Chagas worked at the Oswaldo Cruz Institute in Rio de Janeiro, Brazil.

In 1909, the Oswaldo Cruz Institute sent Dr. Chagas to investigate an outbreak of malaria which was hampering the construction of a new railroad through a remote area of Brazil covered with thick forests and jungles. Dr. Chagas arrived at a small city called Lassance near the São Francisco River in the Amazon and began searching for the cause of what was responsible for killing those railroad workers.

Dr. Carlos Chagas at the Oswaldo Cruz Institute Rio de Janerio, Brazil

Over a period of two years Dr. Chagas observed the lifestyles and living habits of local people. Many people were living in ramshackle tin roofed hovels or in temporary camps which used canvas tents set up next to the railroad tracks as primary shelters. He soon discovered a bug which he suspected had something to do with what was causing sleeping sickness among the locals and railroad workers.

Locals had many names for the bug. They called it the “Assassin Bug” or “the Barber”, primarily because the bug had a habit of feeding on the faces of its hosts, usually at night. Today, most people refer to that insect either as the “Kissing Bug” or Triatomine. Dr. Chagas eventually discovered the link between the bug and its victims by examining the bug’s feces and the blood of a sick three-year-old girl.

Dr. Michael Z. Levy of the University of Pennsylvania’s Perelman School of Medicine, credits Dr. Chaga’s intuition about suspecting the kissing bug as a possible vector, noting that over 100 years ago Chagas located the parasite in the bug long before actually seeing a single case of the disease. Eventually, Dr. Chagas saw a flagellate protozoa under his microscope in samples of the girl’s blood which were identical to ones found in the feces of the kissing bug. He named the parasite after his mentor Oswaldo Cruz, hence the modern name for the parasite; Trypanosoma cruzi.

T.Cruzi Protozoa
Photo courtesy of the Centers for Disease Control and Prevention

A deadly protozoa

Dr. Chagas believed that armadillos were the natural “reservoir” for the parasite. He suspected that kissing bugs were primarily feeding on their armadillo hosts while also occasionally biting humans and thus transmitting T. cruzi. Today, we know that kissing bugs feed on a wide variety of mammals including opossums, raccoons, wood rats, mice, dogs and etc.
According to the Chagas Disease Foundation, the T.cruzi parasite affects about 20 million people in Mexico, Central and South America. The Foundation says that the disease is especially prone to affect younger people and those living in rural or semi-rural areas. Those factors make it exceptionally deadly amongst people living in impoverished areas.

Transmission of the parasite

Debris of temporary immigrant camp near the Arizona-Mexico border
Perfect breeding ground for the Kissing Bug
Photo courtesy: of Lance Altherr

The U. S. Centers for Disease Control and Prevention says that approximately 8 Million people have Chagas disease throughout Mexico, Central America, and South America. The CDC also estimates that as many as 300,000 cases of Chagas could be in the U.S. today. According to the CDC, many people who have been infected with Chagas are unaware that they are carrying it until it becomes life-threatening. It is not uncommon for people to actually have Chagas for many years with little or no symptoms until heart and digestive muscle damage eventually gets noticed.

Where Kissing Bugs have been spotted in the U.S.
Photo courtesy of the Centers for Disease Control and Prevention

Because of its ability to remain hidden in its hosts for many years, Chagas is especially worrying for people receiving blood transfusions or organ donations from infected donors. Chagas can also be transmitted from mother to child through birth or via breast-feeding.
A typical transmission of T.cruzi involving a kissing bug and human usually begins at night. Kissing bugs generally hide in crevices in the walls or roof of a structure by day and then climb onto their host at nighttime while they are sleeping. The kissing bug will then feed on its host, usually near the eye, lip or nose. As the insect fills its body with blood from its host, the increased fluid pressure pushes excrement from its abdomen. A sleeping person who has been bitten may inadvertently scratch the feces into the wound site or onto their mouth. A common indication of a kissing bug bite is known as the Romaña sign. This is expressed as a general puffy swelling around the eye caused by scratching or rubbing the kissing bug’s feces into the eye.
Romana Sign - Chagas- T.cruzi
Photo courtesy: Falcultad de Medicina UNAM

What this research means for victims of bedbugs

Arguably, the most important finding in this study centers around the research regarding the transmission of T.cruzi between mice and bedbugs. That is because one of the researchers from the team in Peru, who is also a veterinarian, said that mice actively hunt bedbugs. Another Peruvian researcher, a biologist, mentioned that T.cruzi grew exceptionally well in the guts of the bedbugs they studied for their experiments. That combination poses a very real chance that that bedbugs infected with T.cruzi can eventually find human hosts.

Hypothetical T.cruzi transmission to humans
Property of Products for Peaceful Operations

Understanding the legal concept of habitability and how it relates to this research

Throughout America most state courts handle disputes between tenants and landlords using contract law. Those courts will often use a lease agreement between a landlord and tenant as the standard contract on which they will base most of their decisions. The lease agreement usually forms the contract which memorializes an exchange of money from the tenant to the landlord in consideration for the use of a habitable dwelling for a prescribed period of time.

The key word here is habitable. In American contract legal theory each contract must contain the element of “consideration” or it is not enforceable. In other words, a landlord cannot receive money for a dwelling which has no commercial value. Traditionally, rental properties are considered uninhabitable when there are substantial defects within the dwelling which render the property unsafe, or otherwise adversely affect the health of the occupants.

Some examples of habitability issues could be an apartment with no running water, no heat during the winter, large holes in the ceiling or roof and etc. Basically, any defect which would convince a reasonable person to avoid paying any money for the privilege of occupancy. Courts will typically void any contract between a landlord and tenant whenever the dwelling is determined to be uninhabitable. In the eyes of the court, such a dwelling has no commercial value and thus, there can be no “consideration” in the formation of that contract. A landlord would be ordered to return the tenant’s money and any other fees associated with that property.

Traditionally, American courts have not recognized bedbugs as a habitability issue. Many courts allow landlords broad discretion when it comes to enforcing pest-control clauses which have been inserted into lease agreements. Unfortunately, most tenants do not understand that they can be harmed by signing a lease agreement which contains provisions which exclude the landlord for pest-control liability.

This new bedbug research could potentially change traditional notions regarding habitability. That is because bedbugs have now been proven to be a potential vector of a deadly disease. A court must now decide whether the presence of bedbugs represents a potential danger to the health or safety of a prospective tenant.

Sadly, the American legal system is rigged against low-income tenants. In larger cities rental properties are often owned by large consortiums or corporations with considerable legal power. It is not uncommon for a group of wealthy property and real estate business owners to join together and purchase multiple- dwelling rental properties.

Those property owners often contribute substantial donations to the election campaigns of local judges. Those judges are therefore often reluctant to enforce policies which might be more favorable towards tenants. Although those judges will not openly deny most valid habitability claims, they will not grant tenants the advantage in most bedbug cases. Unless there has been clear, documented proof of misrepresentation by the property owner, most tenants will not prevail in lawsuits involving bedbug claims.


The Big Homie Joel Z. Williams
Director: Products for Peaceful Operations

Personally, I feel that it is very unlikely that bedbugs will transmit Chagas to humans. That being said, if it ever does happen you can bet that some poor tenant made ill or killed as a result of Chagas disease will be in large part because a landlord was simply too cheap to treat a bedbug infested apartment. My hope is that public outcry will eventually become so strident that courts will have no choice but to recognize the presence of bedbugs within a dwelling as something which adversely affects the health and safety of its occupants. Until that time, please use the Williams method to apply CimeXa desiccant powder, make passive monitoring pitfalls, create Co2 bedbug traps and practice mattress and furniture encasement using contractor’s plastic sheeting. Learn how to do that here: