Scientists Crack Genome Sequence of a Major Parasitic Pathogen
Contact: Brenda Hudson, Academic Health Center,
Scientists Crack Genome
Sequence of a Major Parasitic Pathogen
Global public health threat Cryptosporidium parvum
affects humans and animals
MINNEAPOLIS / ST. PAUL (March 25, 2004) ? University of
Minnesota researchers have completed sequencing the genome of an intestinal
parasite that affects healthy humans and animals and can be fatal to those with
compromised immune systems, such as AIDS patients. The results will be published
in the journal Science on March 25.
The parasite, Cryptosporidium
parvum, is considered a major public health threat for which there is
currently no known treatment or prevention. The gene sequencing will allow
researchers to develop new ways of early diagnosis, prevention, and treatment
of this parasite.
?This is a horrible, hard-to-treat condition, largely
because we lack a basic understanding of the genetic makeup of the organism,?
said Mitchell Abrahamsen, Ph.D., principal investigator, and faculty member of
the University of Minnesota College Veterinary Medicine. ?In fact, since
analyzing the complete genome sequence, we now realize that many of the
conventional antiparasitic drugs that have been used in an attempt to treat
infected individuals have failed because the biochemical targets of the drugs
are absent in C. parvum.?
spread through feces of infected hosts and results in an acute case of diarrhea
in humans and animals. Most people with an intact immune system recover after several
days; however, for the young, elderly, and immunosuppressed individuals,
symptoms can be severe and require intravenous fluid therapy to deal with the
Infection by Cryptosporidium
is also one of the major causes of neonatal diarrhea in calves, contributing to
significant economic loss in the dairy and beef cattle industries. In 1992, a
USDA study revealed that more than 80 percent of farms surveyed were positive
Despite intensive efforts over the past 20 years, public
health authorities have found prevention difficult. The parasite is highly
resistant to environmental stresses, including chlorine treatment of community
water supplies. As a result, the parasite is a significant water- and
food-borne pathogen. In recent years, there have been major outbreaks of C. parvum in Milwaukee, Wis., and the
Minnesota Zoo in Apple Valley, Minn.
?The genome sequence sheds new light on the genes and
biochemical pathways in the parasite, and the research offers a starting point
for defining the mechanisms by which the organism causes disease, and helps
devise new strategies to detect, prevent, and treat C. parvum infection in humans and animals,? said Vivek Kapur, BVSc,
Ph.D., co-principal investigator, faculty member of the University of Minnesota
Medical School and College of Veterinary Medicine, and director of the
university?s Biomedical Genomics Center and Advanced Genetic Analysis Center,
where the genome sequencing was carried out.
During the sequencing project, scientists discovered
several genes and unknown biochemical pathways with great similarities to
bacterial and plant counterparts. ?These biochemical pathways are very
different from those present in humans and will provide new targets for
designing effective and safe drugs against C.
parvum that should have little activity or toxicity for humans,? said
The sequencing project
represents part of an ambitious University of Minnesota ?microbial
pathogenomics? research program to sequence the genomes of a wide range of
human and animal pathogens. This information then can be used to understand the
mechanisms by which these pathogens cause disease.
The Academic Health Center is home to the University of Minnesota?s
seven health professional schools and colleges as well as several
health-related centers and institutes. Founded in 1851, the University is one
of the oldest and largest land grant institutions in the country. The AHC
prepares the new health professionals who improve the health of communities,
discover and deliver new treatments and cures, and strengthen the health