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Reviews and Resources
BOOKS
Vibrio cholerae: Genomics
and Molecular Biology
S. M. Faruque and G. Balakrish Nair (ed.).
Caister Academic Press, 218 p., $310.
Waterborne infections and epidemics are
recurring events in human history, as highlighted by the seven pandemics caused by
the bacterium Vibrio cholerae. An exhibit
at the New York Historical Society (4
April—2 November 2008) covered the
three waves of cholerae epidemics that hit
Gotham in 1832, 1849, and 1866. The
exhibit provided a human interest backdrop for the 13 scientific chapters in this
book (written by leading experts). Death
from dehydration was typical following
the gastroenteric infection during those
years, as is the case today in many parts of
the developing world. As laid out in the
first chapter, Filippo Pacini (1854) first
discovered and Robert Koch (1883) described the organism. The physician John
Snow first pinpointed contaminated water
as the source of cholerae during an outbreak in London. The fact that cholerae
outbreaks have been reported as recently
as 2008 (Vietnam), illustrates that the battle against this pathogen is far from over.
Six of the seven cholerae pandemics
originated in the Ganges Delta region of
India, but soon spread as far afield as
sub-Saharan Africa and Peru. Most of the
book explores the intricate genomics, signaling, virulence factors, and evolution
that enable these environmental, salt-loving bacteria to transform into human
pathogens. Over 200 serogroups of V.
cholerae have been identified on the basis
of epitopic variations in the cell surface
polysaccharide.
The O1 and O139 serogroups have been
responsible for most of the major outbreaks. The numerous genes and signaling
factors e.g. quorum-sensing factors and
second messengers including c-di-GMP
586 Y Microbe / Volume 3, Number 12, 2008
that work together to regulate the virulence regulon of V. cholerae and biofilm
formation are clearly described in the relevant chapters (chapters 5, 7, and 9).
The identification of environmental and
pathogenic multidrug-resistant V. cholerae variants is another sobering reminder
of the rise in antibiotic resistance among
bacteria. In this case, the genomic plasticity of V. cholerae makes the search for an
effective antimicrobial agent more difficult. However, there is growing evidence
that lytic bacteriophages may be important in limiting its epidemic cycle. Seven
filamentous phages have been identified in
association with different V. cholerae isolates. The life cycle and evolution of the
lysogenic phage, CTXØ, which encodes
cholerae toxin is elaborated upon further
in chapter 4.
The recent emergence of pathogenic
clones of non-O1, non-O139 V. cholerae
strains reinforces the need for continued
surveillance of this bacterium. Overall, the
book is a valuable compendium for researchers wishing to have quick access to
the latest findings regarding a bacterium
that serves as a paradigm for extracellular
pathogens.
Zeena Nackerdien
Rockefeller University
New York, N.Y.
Forgotten People, Forgotten
Diseases
Peter J. Hotez. ASM Press, Washington,
D.C., 2008, 215 p., $39.95.
In this relatively short (165 pages of text)
book, the author discusses the impact of
neglected tropical diseases (NTDs), which
are found mainly among the poor in Third
World and developing countries. These
diseases are not “emerging,” having been
around for centuries, and, since they are
found relatively rarely in the developed
world, are not “sexy” enough to find their
way into the media. Approximately
530,000 persons a year die from such diseases, a small number when compared to
those who die from natural disasters,
AIDS, or malaria. Nevertheless, although
they typically have a low mortality, NTDs
tend to be chronic and often stigmatize the
patient.
NTDs include diseases spread by helminths, protozoans, and bacteria. The
most common NTDs are ascariasis, trichuriasis, and hookworm infection, and
are described by the author as “the unholy
trinity.” They are transmitted through the
soil and find a home in the human gastrointestinal tract. The author notes that close
to 1 billion people are infected with these
worms and that children are more often
infected than adults. Chronic infections
among children impair their physical
growth, mental development, and school
performance. The most effective method
of control is the deworming of large populations with antihelminthic drugs known
as benzimidazole antihelminthics.
Schistosomiasis is most commonly
found in the poorest regions of Africa.
Again, children and adolescents are at
greatest risk of acquiring this disease.
Praziquantel is considered the drug of
choice in treatment.
Subsequent chapters describe the filarial
infections (elephantiasis and guinea
worm), river blindness and trachoma,
mycobacterial diseases (Buruli ulcer and
leprosy), the so-called kinetoplastid infections, i.e., trypanosomiasis, Chagas’
disease, and leishmaniasis.
Most of the diseases mentioned to this
point typically occur in rural settings. In
the chapter entitled “The Urban Neglected Tropical Diseases,” leptospirosis, dengue, and rabies are considered.
As opposed to mass vaccination of dogs
against rabies in western countries, a
major problem is the large number of
unvaccinated stray dogs (e.g., in India
and Bangladesh and urban centers of
other developing countries) in areas
where rabies deaths are high.
The chapter on NTDs of North America
describes poverty-associated diseases including toxocariasis, toxoplasmosis, and
giardiasis in the United States; trichinosis
among the Inuit; and even elephantiasis in
the Caribbean. Giardiasis and toxocariasis
are most common, the number of cases of
other NTDs being relatively low.
The last two chapters of the book describe the major organizations involved in
NTD control and look at future trends in
controlling these diseases. Organizations
involved in the development of new drugs
and vaccines are listed as are new drug
targeting NTD’s developed between 1975
and 2004. Unfortunately, many major
drug companies have little incentive to develop projects targeting diseases that exclusively afflict exclusively poor populations.
The format of the book makes it easy to
read since the material is well explained
and presented in an interesting manner. At
the end of each chapter there is a list of
summary points which condense the material covered, and easily understandable
figures describing the life cycle of parasites
are presented. A one-page appendix lists
the NTDs. Besides a list of references at the
end of the book, there is a section of Notes
covering each chapter. Twelve pages of
attractive color plates emphasize material
covered in eight of the book’s chapters.
Fred A. Rosenberg
California Lutheran University
Thousand Oaks, Calif.
Volume 3, Number 12, 2008 / Microbe Y 587