Vaccines and Antivirals: Grand Challenges and Great Opportunities
Ventura County Public Health Identifies 19 Cases From Last Year That Appear To Be Leptospirosis
VENTURA COUNTY, Calif. – After an investigation that began in October of last year, Ventura County Public Health identified 19 people who had illnesses that appear to be leptospirosis.
According to the county-based health agency, the illnesses were first reported in January of 2024, were publicly acknowledged in November, and were largely limited to agricultural workers in local caneberry fields.
The bacterial infections were suspected to be acquired locally instead of from travel and there is no known health risk to the general public through contact or the consumption of locally-grown berries noted Ventura County Public Health.
Preliminary results from environmental sampling found the presence of Leptospira - the bacteria that causes the illness - in samples from mud, wet soil, and standing water, but not in irrigation water, potable water, or growing material used on local farms detailed Ventura County Public Health.
Leptospirosis is transmitted through contact with the urine of sick animals, such as livestock or rodents, and agricultural workers doing fieldwork are at greater risk of exposure explained Ventura County Public Health.
Notably, leptospirosis is not typically spread from person to person added Ventura County Public Health.
Symptoms of leptospirosis range from mild flu-like symptoms - such as fever, muscle pain, and/or headaches - to severe complications of the respiratory system or internal organs detailed Ventura County Public Health.
If diagnosed early, most cases can be successfully treated with antibiotics shared Ventura County Public Health.
If you experience those symptoms and have a risk of exposure, it is recommended you contact a medical professional.
Without treatment, leptospirosis can lead to kidney damage, meningitis, liver failure, difficulty breathing, and death stated the U.S. Centers for Disease Control and Prevention.
Ventura County Public Health recommends those working in conditions that increase their exposure to leptospirosis to take the following precautions:
Saving Humanity From Leptospirosis
Research Fields and Areas Infectious Diseases Control
Leptospirosis is a bacterial disease that is found throughout the world, mainly in tropical and subtropical regions. Contracting leptospirosis causes illness, such as jaundice, pulmonary hemorrhage, and kidney failure. In most severe cases it can lead to death. Japan is not spared from this disease, since many infections have occurred in southern Kyushu.Despite the seriousness of this disease, there is little known about the true nature of the malady. To address this situation, this project conducted research with the aim of establishing preventive measures and developing a rapid diagnostic method including a detailed study in the Philippines, where the disease is widespread. The project successfully achieved many outcomes that will hopefully contribute in controlling leptospirosis.
Principal investigator (Japan):Professor YOSHIDA Shin-ichi
Faculty of Medical Sciences, Kyushu University
After graduating from the School of Medicine at Kyushu University, he studied immunology and bacteriology at Kyushu University's Graduate School of Medical Sciences. He then served as instructor, associate professor, and professor of microbiology at the University of Occupational and Environmental Health, Japan. Starting 1998, he served as professor in the Faculty of Medical Sciences, Kyushu University. His research covers pathogenic factors and the biology of pathogenic bacteria, such as Leptospira, Legionella, O157, Streptococcus, and Vibrio.
Japan perspective
Conquering disease is the shared aim of humanity, and to take part in that endeavor was a powerful motivation. By collaborating with researchers in the Philippines, this SATREPS project took up the challenge of conquering leptospirosis by a) determining the incidence of leptospirosis, b) developing a fast diagnostic method, c) working towards production of a vaccine, d) raising awareness and e) explicating the pathology of the disease. It was highly satisfying to have been able to meet most of these goals.
Principal investigator (The Philippines):Professor Nina G. Gloriani
Department of Medical Microbiology, College of Public Health, University of the Philippines Manila
She obtained her Ph.D. In Microbial Immunology and Immunochemistry from the University of Melbourne in Australia. She served as Dean of the College of Public Health, University of the Philippines Manila from 2007 to 2013, which included the period of the SATREPS project.
Philippin's perspective
Overall, I would like to believe that we accomplished much over the last 5 years. The capacity building component of the LepCon program in terms of infrastructure and human resource development were the best things that happened. We have a state of the art leptospirosis diagnostics facility that we could use for other pathogens as well, and our faculty and staff, including students were trained and learned many new advanced techniques both in Japan and in this renovated laboratory in the college. More students, both graduate and undergrads, are now able to use the laboratory facilities for their special studies, research projects, thesis and dissertation. We have generated several publications, disseminated our research findings in different fora, and the level of knowledge about leptospirosis in the Philippines has been enhanced considerably because of these. Technical cooperation with the Japanese scientists was excellent and the interaction fostered good professional and personal relations which contributed a lot to the successful outcome of the LepCon program technical cooperation.
Determined the incidence of leptospirosisLeptospirosis is a zoonotic disease, which means that it can be passed from animals to humans. Project researchers studied the state of infection of animals in the Philippines that humans have a high chance of coming into contact with. The results showed a high incidence of Leptospira antibodies* in rats (92%), carabao (water buffalo, 82%), dogs (83%), and pigs (67%) in urban areas like Manila, making it clear that people are constantly exposed to the danger of Leptospiral infection.
The fact that an animal has Leptospira antibodies means that, at the very least, the animal has been infected with Leptospira bacteria in the past, and indicates that there is a possibility that it still carries the bacteria in its body.
Enabled early diagnosisLeptospirosis begins with symptoms such as a fever and headache, just like the symptoms of an ordinary cold. That similarity means that in a large number of cases the disease goes unnoticed until it has become severe. For this reason, project researchers developed a practical method for achieving a definitive diagnosis of leptospirosis at an early stage. This is potentially life-saving, because antimicrobial agents can be used to treat the disease if an early diagnosis is obtained.
Confirmed effectiveness of a vaccineThe most important countermeasure against infectious disease is prevention of infection, and inoculation using a vaccine is cited as an effective means of preventing leptospirosis. Therefore, project researchers developed an inactivated vaccine-a vaccine created based on bacteria that has had its infectiousness and toxicity eliminated through the use of chemicals. The effectiveness of the leptospirosis vaccine was confirmed using hamsters, making it possible to inoculate livestock and pets. This success can potentially avert damage to industry due to infection of livestock and contain infection from pets to humans.
Production of a diagnostic kit is expected to make it simple to perform a definitive diagnosis of leptospirosis. A prototype has already been made, and is currently being investigated in preparation for commercialization. Development of an effective vaccine for humans is also anticipated.
People can be infected by Leptospira from animals. How exactly does this happen?
Prof.YOSHIDA
There are two kinds of Leptospira -pathogenic Leptospira, which causes illness (infectious disease) in humans and animals, and non-pathogenic Leptospira, which does not. Non-pathogenic Leptospira dwells in soil and in fresh water, such as waterways, puddles, and rivers. Pathogenic Leptospira, on the other hand, usually inhabits the kidneys of animals without causing illness to the host (i.E., rats). When excreted in the urine, it survives in soil and water. There, humans and livestock that are susceptible to it come into contact with the bacteria, and are infected through the skin or mucous membrane. The infection then causes various states of illness ranging from mild, with symptoms such as fever and muscle ache, to severe, including jaundice, kidney failure, and pulmonary hemorrhage.
Can pets imported to Japan carry leptospirosis?
Prof.YOSHIDA
Leptospira infects many animals, including pets and livestock. Mice and some other animals do not develop the disease, but become carriers, with the bacteria dwelling in their kidneys. Many pets are imported into Japan today, and they may be possibly infected with Leptospira. Imported flying squirrels have been confirmed as a source of infection, with recent cases of people being infected by them.
You discovered a new species of Leptospira , right?
Prof.YOSHIDA
Leptospira dwells in soil and water, but because it shares its habitat with many other germs and molds, attempts at cultivating Leptospira usually result in a proliferation of other microorganisms that impedes the growth of Leptospira. What was needed was a culture medium that allows Leptospira to propagate while suppressing competing growth. We tested a variety of antimicrobial and antifungal agents, and after much trial and error, we developed a combination that was a good match with this objective. We named it STAFF, after the initials of the antimicrobial agents. When we sampled water from a puddle near a swimming pool and cultured it using STAFF, one of the Leptospira that emerged from the culture seemed more rugged and harder than others. Suspecting it was something that had not been seen before, we conducted tests, and were able to report discovery of a new species. We named it L. Idonii, inspired by Professors Ryukichi Inada and Yutaka Ido of Kyushu University, who were the first in the world to discover that Weil's disease was an infection of Leptospira. Professor Inada already had a bacteria named after him, so we named this new strain after Professor Ido.
What difficulties did you experience during the project?
Prof.YOSHIDA
As part of this project, a laboratory, hamster facility, and an animal testing laboratory were installed for Leptospira research at the College of Public Health, University of the Philippines Manila. The people involved in the construction were tremendously helpful, and we are particularly indebted to the coordinators and Professor Emeritus Yasutake Yanagihara who exerted great effort to make sure that the devices and equipment delivered to the lab were the models we wanted. The process of exporting hamsters was also complicated, and we had to put in a good deal of thought to ensure that the MTA (Material Transfer Agreement) and other contract-related procedures would go smoothly. The research itself was not a problem, because we are used to the difficulties of conducting research.
One of the expected developments is a diagnostic kit for leptospirosis. What is a diagnostic kit?
Prof.YOSHIDA
Generally speaking, there are two types of diagnosis of infectious diseases-clinical diagnosis and laboratory diagnosis. Clinical diagnosis of Leptospira is difficult, so a laboratory diagnosis must be conducted in order to be certain. In order to determine if a patient has an infection, one approach is to look for pathogen-derived proteins and genes in the body of the subject suspected of being infected. Alternatively, you can study the antibodies and immune response to the pathogenic agent of the subject when our project started, testing was generally only possible at properly equipped laboratories, but that made it impossible to test outpatients, or to test at the patient's bedside or in the field. To overcome that limitation we attempted to develop simple and rapid diagnostic kits that could be used in such situations and produce quick results. Development of the antigen detection kit came to a standstill at the mass production stage, but mass production of the antibody detection kit is feasible.
A vaccine for humans will hopefully be created soon. How long is that likely to take?
Prof.YOSHIDA
A vaccine that is effective on humans already exists, and is used in Japan to inoculate farm workers and other high-risk people. It has helped to lower the number of Leptospiral infection in Japan. This SATREPS project identified serotypes endemic to the Philippines, made a vaccine from them, and confirmed its effectiveness on hamsters. The vaccine's effectiveness in livestock still needs to be confirmed before beginning human inoculations. The researchers in the Philippines will handle that process, and we are confident that they will do a good job.
Please see the project's webpage for details.
Infectious Diseases Control
Republic of the Philippines
Understanding Leptospirosis
Leptospirosis is a bacterial disease that causes illness in humans through contact with infected animal urine and contaminated water. It is not a disease that spreads from person to person; when clusters of people are infected it is because they have been exposed to the same source. It can be hard to diagnose, as its symptoms look similar to a variety of other illnesses, including influenza and Covid-19. The way it presents can range from a minor flu-like illness to more serious symptoms needing hospital admission, such as meningitis and kidney or lung failure. In some cases, it can be fatal, and in others, the effects can linger for some time.
Professor Jackie Benschop from the School of Veterinary Science has been researching leptospirosis for more than a decade. 'In New Zealand, it is largely a disease of farmers and meat workers, who are more likely to be in direct contact with animal urine,' she says. 'Livestock species including sheep, cattle, deer and pigs, as well as rodents, possums and hedgehogs, are carriers.'
As a veterinarian and epidemiologist, Professor Benschop focuses primarily on the biomedical aspects of leptospirosis but is careful to emphasise the importance of also paying attention to the social burden of the disease. 'I was a vet in practice for 20 years before I came to Massey and for some of those years I worked in the meat industry,' she says. 'It's an important industry but often hard.
'The industry does everything it can to stop people getting leptospirosis, including personal protective gear, splash guards and machinery. They do not want their workers getting sick, but most animals who turn up at the works aren't vaccinated and the vaccines that we have for animals don't cover all strains that animals can carry. It is an infection that people can get at work, and they can be sick for a lot longer than just a month or two. There are elements of social justice in leptospirosis and I'm quite connected with those because of where I've come from.'
A case-control study of the risk factors for leptospirosis in New Zealand
From left: Stuart Littlejohn, Dr Shahista Nisa, Dr Ahmed Fayaz, Associate Professor Gerard Prinsen, Professor Jackie Benschop, Associate Professor Polly Yeung and Dr Julie Collins-Emerson.
Currently, Professor Benschop is completing a case-control study, funded by the Health Research Council, into the risk factors for leptospirosis in New Zealand. Ninety-six leptospirosis patients and 300 controls are included in the study. Although the results are still being analysed, so far they show that patients who had leptospirosis were twice as likely to have seen evidence of rodents than those in the control group – the first time this has been demonstrated in New Zealand. The results also show that contact with cattle is a risk factor and that covering cuts on hands offers good protection against infection.
In addition to a first interview with recently ill patients, the study also involves following up with patients in the longer term. 'We asked them questions about their symptoms now, how long they had them for, and how severe they were, and over half of them still have at least one symptom about nine months later,' says Professor Benschop. 'We thought it would be nearer a quarter or a third, and this is a big issue in terms of compensation. Many are back at work, but they're not necessarily that well and some of them cannot go back to work. Globally, that's not really recognised.
'This is the first time we've been able to follow up with patients with leptospirosis for that long. It's been a good case series of how long people are sick, how it's affected their social life, and whether they feel supported by their family and their work. We also asked about their mental health and psychosocial functioning. I do think there's a responsibility not only to do this work but also to value what people share with you. It's humbling to hear each person's story and the trust they have in you to share that.'
Professor Benschop is part of the World Health Organization's Global Leptospirosis Network. 'We have done work, for example, in Brazil and other places that are considered to be low and middle-income countries. I have personally been involved in developing guidelines and sharing our experience with animal vaccination. Leptospirosis can live in water and so it is climate-sensitive. When water levels rise and flooding occurs, like that seen in Manila, Sri Lanka, Bangladesh and India, rodents and people all gather on higher ground. People walk in floodwater and their skin becomes macerated, allowing leptospirosis in, as well as through mucous membranes and damage in the skin. I'm one of the international experts who get called into those discussions. It's interesting to note how leptospirosis overseas is different to how it is in New Zealand but also how it is similar.'
UN Sustainable Development Goals Jackie Benschop
Learn more about the researcher understanding leptospirosis and the importance of paying attention to the social burden of the disease.
Professor Jackie Benschop BVSc, PhD
Professor of Veterinary Public Health
Professor Jackie Benschop is Co-Director of Massey University's Molecular Epidemiology and Public Health Laboratory (mEpiLab), OIE collaborating Centre for Veterinary Epidemiology and Public Health.
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