Rat fleas can cause plague-like disease

Taiwan, November 26: Brown rats, the most common and biggest rats found in Europe, can be possible carriers of bacteria that can lead to a serious heart disease among humans, says a latest study.

According to the study published in the December issue of Journal of Medicine Microbiology, over 20 species of Bartonella bacteria have been found since the early 1990s. These bacteria are considered zoonotic pathogens because they can inflict serious health conditions such as heart disease and infection of the spleendefine and nervous system.

The lead study author, Professor Chao-Chin Chang of the National Chung Hsing University in Taiwan, said that Bartonella rochalimae is a new species that was discovered in a patient with an enlarged spleen. This patient is known to have traveled to South America.

He further said that "this event raised concern that it could be a newly emerged zoonotic pathogen. Therefore, we decided to investigate further to understand if rodents living close to human environment could carry these bacteria."

This latest finding has led the other scientists to further investigate in order to have a clear understanding if rodents close to the human environment could be possible carriers of the bacteria.

The scientists have proven that rodents could indeed carry pathogenic species of Bartonella including B. elizabethae which can cause endocarditis. Another specie is the B. grahamii that causes neuroretinitis in humans.

Scientists, however, are not yet completely sure regarding the main route of transmission. But these infections are believed to be spread by fleas.

It is also included in the Journal that Ctenophtalmus Bartonella bacteria can transmit different species of Bartonella bacteria. They are basically the fleas that can be found on bank holes and can live on gerbils, cotton rats and brown rats.

Professor Chang also added that they “analyzed bacteria found in Rattus norvegicus in Taiwan.” The brown rat is also the most common rat in Europe. "By analysing the DNA of the bacteria, we discovered a strain that is most closely related to B. rochalimae, which has been isolated recently from a human infection in the United States," he added.

Also part of their study was to take samples from 58 rodents consisting of 53 brown rats, 2 mice and 3 black rats. Scientists observed that six out of the 58 rats were carriers of Bartonella bacteria and five were brown rats.

It was also disclosed that four of the rodent samples were carrying B. elizabethae, and one of the black rats carries B. tribocorum. Researchers also noticed that one previously unidentified strain in rodents was known to be close to B. rochalimae.

Professor Chang however cleared that they are not yet sure that the common brown rat is spreading B. rochalimae because they only used a small sample size. “These results raise concerns about the existence of other reservoirs and vectors for this emerging infection. This certainly warrants further investigation," he added.