An international group of researchers working in more than 20 laboratories around the globe have determined genetic blueprints for the parasites that cause three deadly insect-borne diseases: African sleeping sickness, leishmaniasis and Chagas disease. The research, funded in part by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, is published in this weeks issue of Science. Knowing the full genetic make-up of the three parasites Trypanosoma brucei, Trypanosoma cruzi and Leishmania major could lead to better ways to treat or prevent the diseases they cause.
Although relatively unfamiliar in the United States, the collective misery caused by these diseases throughout the world is considerable. Having these genomes in hand will give us many new targets for drug and vaccine development, says NIAID director Anthony S. Fauci, MD.
All three diseases are spread by insects. T. brucei, which causes sleeping sickness, is spread by the tsetse fly and is found in sub-Saharan Africa. The World Health Organization estimates there may be as many as 500,000 cases of sleeping sickness each year. If left untreated, sleeping sickness is fatal. Various forms of leishmaniasis are spread by the sandfly and are endemic in 88 countries on five continents. Visceral leishmaniasis, also known as kala azar, is the most severe form of the disease and causes high fever, a swollen spleen and severe weight loss before killing its victims. Cutaneous leishmaniasis, also known as Baghdad boil, produces numerous skin ulcers that can leave sufferers permanently scarred. Some 1,000 American service members have been diagnosed with cutaneous leishmaniasis according to testimony by Walter Reed Army Institute of Researchs Alan Magill, MD, at an Institute of Medicine meeting in May 2005. T. cruzi causes Chagas disease and is spread through the infected feces of an insect sometimes called the kissing bug for its habit of biting near a persons mouth. Found throughout Central and South America, Chagas disease is particularly prevalent among the poor and claims 50,000 lives each year.
NIAID supported the sequencing projects through grants to Kenneth Stuart, PhD, and Peter Myler, PhD, of Seattle Biomedical Research Institute (SBRI); to Najib El-Sayed, PhD, of The Institute for Genome Research (TIGR), Rockville, Md.; and to Bjorn Andersson, PhD, of the Karolinska Institute in Stockholm, Sweden.
One of the biggest surprises to come out of the genome sequencing projects is that these parasites despite major differences in how they are spread and how they cause disease nevertheless have a core of 6,200 genes in common, says Martin John Rogers, PhD, of NIAIDs Parasitology and International Programs Branch. At a genetic level, the similarities among these parasites outweigh their differences. The shared genes give scientists a vastly expanded array of targets for development of new drugs that conceivably could work against all three parasites, explains Rogers. Conversely, he adds, analyzing the relatively smaller ways in which the organisms diverge genetically could help researchers design vaccines, drugs and improved diagnostics targeted to each of the three parasites.
In addition to the publication of the three genomes, this weeks issue of Science also includes a paper by NIAID grantee Rick Tarleton, PhD, of the University of Georgia, Athens, detailing T. cruzis proteome the set of expressed proteins encoded by its genome. This is a significant achievement, notes Rogers, because T. cruzi, like many parasites, has multiple forms in its lifecycle and produces differing suites of proteins at each stage. The proteomic analysis revealed the presence of numerous stage-specific proteins, providing clues about how the parasite exploits its insect and mammalian hosts. This, in turn, suggests ways to battle the parasite with drugs specific to each life stage, says Rogers. At present, there are few therapies for Chagas disease, the condition caused by T. cruzi parasites, and the available drugs are ineffective and have significant adverse side effects.
Taken together, Rogers says, the wealth of information contained in the sequenced genomes opens new avenues to tackle these often forgotten diseases.
In addition to NIAID, The Wellcome Trust, London, supported the T. brucei and L. major genome sequencing projects.
References:
N El-Sayed et al. Comparative genomics of Trypanosomatid parasitic protozoa. Science DOI: 10.1126 (2005).
N El-Sayed et al. The genome sequence of Trypanosoma cruzi, etiologic agent of Chagas disease. Science DOI: 10.1126 (2005).
M Berriman et al. The genome of the African Trypanosome Trypanosoma brucei. Science DOI: 10.1126 (2005).
AC Ivens et al. The genome of the kinetoplastid parasite, Leishmania major. Science DOI: 10.1126 (2005).
JA Atwood et al. The Trypanosoma cruzi proteome. Science DOI: 10.1126 (2005).
Source: National Institutes of Health
Product Locator: Spring and Early Mother's Day Gift Guide for Infection Prevention Personnel
March 27th 2024Whether it's a spring holiday, birthdays, or no reason at all, infection prevention personnel love to give and receive gifts that help at the end of a stressful day. Infection Control Today® offers some gift ideas for infection prevention personnel and their families.
Catching Up With Vangie Dennis, AORN 2022-2023 President at AORN 2024
March 26th 2024Infection Control Today (ICT) had the privilege of catching up with Vangie Dennis, MSN, RN, CNOR, CMLSO, at the Association of periOperative Registered Nurses' (AORN’s) International Surgical Conference & Expo 2024. As the former president of AORN and an esteemed figure in perioperative services, Vangie Dennis shared insights into her recent endeavors and the exciting new chapter she's embarked upon.
How To Optimize Your Time Management Strategies for the Busy Infection Preventionist
March 25th 2024Is your calendar resembling a chaotic masterpiece of overlapping tasks? Join the club of infection preventionists striving to balance responsibilities. Dive into proven strategies from a fellow infection preventionist to reclaim control of your time, streamline tasks, and boost productivity effectively. This is an IP Lifeline article.
CenTrak Unveils Revolutionary BLE Multi-Mode Platform for Health Care RTLS Solutions
March 22nd 2024CenTrak, the industry leader in real-time location technology, introduces the groundbreaking BLE Multi-Mode Platform, setting a new standard for Real-Time Location Systems (RTLS) in health care. Discover how this innovative solution enhances location data precision and streamlines operations for health care organizations.