“It takes 10 to 14 years to develop a vaccine,” says Dr. Nina Gloriani of the University of the Philippines Manila College of Public Health. And that’s not counting the intervening periods where one attends to other professional and personal activities which also require time and attention. Recently however, she and her team have registered the proof of concept for LeptoVax, the first locally produced vaccine against the Leptospirosis bacteria.
With assistance from the Japan International Cooperation Agency (JICA) and Japan Science and Technology Agency, and in collaboration with scientists from Kyushu University and the Chiba Institute of Science, Dr. Gloriani and her team developed LeptoVax in 2010. It is expected to be used on house pets and livestock to protect them from the Leptospira bacteria which is being transmitted by rats.
Aside from the team’s foreign partners, the project was also supported by the Department of Science and Technology (DOST), particularly the Philippine Council for Health Development.
Over the years, the research team studied the various factors affecting the transmission of Leptospirosis in Metro Manila, using a Geographic Information System (GIS). They also developed diagnostic kits and conducted advocacy campaigns for information and health promotion against Leptospirosis. These came on top of the vaccine which they hope to develop further for human use.
Using samples collected from individuals affected with the bacteria, the team was able to identify several areas nationwide where Leptospirosis strains are present and being spread by rats and other animals. “We actually have around nine regions: from Region 1, 3, 4A, 5, that’s Bicol region. Of course, the NCR. We worked with Region 6, Region 7, Region 8, 10, 11,” Dr. Gloriani says.
In July of this year, the Department of Health declared a Leptospirosis outbreak in several parts of Metro Manila when the number of individuals infected with the bacteria increased. In a news report on DZMM, Health Secretary Francisco Duque said 58 had died out of the 454 patients admitted to hospitals from January to July 2018.
Originally believed to be a seasonal disease which occurs during the rainy season, Leptospirosis has become endemic in some areas, according to Dr. Gloriani. She continues, “For example, Region 6, the Iloilo-Western Visayas region, has a lot of agricultural lands and we have farmers, we have a lot of livestock there. Even without extensive floods, they have many cases.” The rainy season, she adds, only aids in spreading the disease more quickly and affecting more people in populated areas.
Dr. Gloriani warns that despite the common notion in the country that the bacteria spreads when one comes in contact with surfaces having the urine and wastes of rats, research in other countries have also shown that it can be contracted by bats which inhabit caves. She says that it can also spread via water-related activities or sports.
In research papers available on the United States’ Centers for Disease Control (CDC) website, scientists from Brazil, China, Madagascar, and the Union of the Comoros have recorded incidents in some areas in their countries where bats have tested positive for Leptospirosis. The CDC also lists buffaloes, cattle, goats, horses and sheep as among the animals which may aid in spreading the virus.
Asked on what can be done to stem the tide of Leptospirosis in several areas in the country, Dr. Gloriani sums it up in two words: hygiene and sanitation. She says the bacteria spreads due to the problematic waste and drainage situation in many areas of the country. “Until we don’t solve problems in public engineering, Leptospirosis outbreaks will continue,” she emphasized.
Dr. Gloriani’s teammate, Dr. Sharon Villanueva, agrees with correcting the notion that rats are the only culprits in spreading the bacteria. “It is not only spread by rats or during floods or heavy rains and flood. But it can also be spread by other animals like dogs and livestock animals,” Dr. Villanueva says. She adds that Leptospirosis can also be acquired by a person who comes in contact with soil on which the bacteria may be present.
Dr. Villanueva underscores information dissemination and awareness as essential tools in the fight against Leptospirosis. She adds that efforts to address the disease must also involve whole communities and not only those who are have contracted it from exposure.
Dr. Villanueva says that while providing affected patients with prophylaxis can help individuals affected with Leptospirosis, a more holistic approach against the bacteria would be more effective in preventing it from infecting a community. “Of course, we cannot completely eliminate the rats. So, what we have to do is really clean our environment, our surroundings, so as to prevent the infestation of rats,” she says.
Dr. Villanueva has been working with Dr. Gloriani on LeptoVax since 2012. And they have conducted research in various locations in the country where several strains of Leptospirosis exist. In their findings they were able to identify two serovars common in the country: Leptospira interrogans serovar Manilae and Leptospira interrogans serovar Losbanos. They were also able to identify two serogroups: Leptospira interrogans serogroup Grippotyphosa and Leptospira borgpetersenii serogoup Javanica.
While it may still take some time to fully complete LeptoVax trials on animals, Gloriani is hopeful that the findings from their tests will be positive. After successful tests on hamsters, she and her team hope to conduct tests on carabaos and dogs. Dogs, she says, are very susceptible to the bacteria. “We believe that a lot of the human cases also come from dogs. Not just rats contaminating the environment,” she says.
While concentrating on developing the vaccine which would protect livestock and pets from Leptospirosis, Dr. Gloriani, Dr. Villanueva, and the rest of their team, hope to eventually produce a vaccine which can be used by humans. Villanueva however, speaks with caution, as producing one is not an easy undertaking. Short of that, the team hopes, at the very least, to limit the spread of Leptospirosis among animals with which humans spend most of their days.