In childhood:
streptococcus pneumoniae
haemophilus influenza
what else?
viral illness
Chickenpox is caused by Herpes-Zoster virus also known as
"human (alpha> herpes virus 3. Chickenpox is uncommon in adults
but when it occurs may have severe constitutional symptoms.
The rash is vesiculated but starts as macules in randomly
occurring crops and as an enanthem as well. Treatment is
supportive. In the adult watch for pneumonitis which is
associated with the rare fatal case. Smallpox is no longer
considered a problem since the last human case occured in
1977 in Somalia and there are no longer reservoirs in
existence that are known.
---
Tuberculosis (TB) causes more deaths worldwide than any other
infectious disease: in 1995, TB caused an estimated 3 million
deaths, of which 170,000 (6%) occurred among children aged less
than 15 years (1,2). Diagnosing TB in children often is difficult
and relies on clinical judgement and use of algorithms that include
chest radiography and the tuberculin skin test (TST).
---
Fleas-
Of the 2,000 species and subspecies of fleas, only a handful serve as vectors of human diseases. Several
bacterial pathogens of public health importance are maintained and transmitted by fleas, among them,
Yersinia pestis, the causative agent of plague (known in history as black death). Flea-borne human pathogens
are maintained in a zoonotic cycle involving mammalian hosts and fleas. They seldom cause overt disease in
their natural hosts but commonly result in clinical disease, e.g., plague, murine typhus, and cat-scratch
disease, in humans. The rapid spread of pathogens to human populations is due to the frequent feeding
behavior and extraordinary mobility of fleas. Flea-borne diseases are widely distributed throughout the world, in
the form of endemic foci, where components of the cycle are present; however, these diseases become
epidemic in human populations when infected mammalian hosts die and their fleas leave in search of a
bloodmeal. Of flea-borne bacterial pathogens (e.g., Y. pestis, Rickettsia typhi, R. felis, and Bartonella
henselae), the most studied and reviewed is Y. pestis.
The classic cycle of R. typhi, the etiologic agent of murine typhus, involves rats (Rattus rattus and
R. norvegicus) and the rat flea, Xensopsylla cheopis
Table 3. Comparison of Rickettsia felis with other vector-borne Rickettsiae
Species
Vector
R. prowazekii
- louse
R. typhi
-flea
R. canada
- tick
R. felis
- flea
R. akari
-mite
R. australis
- tick
R.ricketsii
- tick
R. conorii
- tick
.
ABDU AZAD
Foodborne diseases have a major public health impact (Table 1; 1).
In the United States, each year foodborne
illnesses affect 6 to 80 million persons, cause 9,000 deaths,
and cost an estimated 5 billion U.S. dollars (2).
The epidemiology of foodborne diseases is rapidly changing
as newly recognized pathogens emerge and
well-recognized pathogens increase in prevalence or become
associated with new food vehicles (Table 2). In
addition to acute gastroenteritis, many emerging foodborne
diseases may cause chronic sequelae or
disability. Listeriosis, for example, can cause
miscarriages (3) or result in meningitis in
patients with chronic diseases (3). Toxoplasmosis is an
important cause of congenital malformation (4), and Escherichia
coli O157:H7 infection is a leading
cause of hemolytic uremic syndrome, the most
common cause of acute kidney
failure in children in the United States (5).
Salmonellosis can cause invasive disease (6) or
reactive arthritis (7),
and campylobacteriosis can lead to Guillain-Barré syndrome,
one of the most common causes of flaccid
paralysis in the United States in the last 50 years (8).