Publication of the Bureau of Epidemiology & Disease Control Services

November/December 2002, Vol. 16, No. 6

West Nile Virus Spreads Across Country,
Likely to be Found in Arizona Soon
By Craig Levy

In preparation for the inevitable
horse. In addition, the University
This year was characterized by
of Arizona’s Veterinary Diagnostic
significant West Nile virus (WNV)
arrival of WNV in Arizona, state
Laboratory tested over 160 dead
activity throughout most of the
and county health officials in
birds. All were negative for WNV.
country. As of October 17, more
Arizona have enhanced surveilSurveillance efforts did detect
than 3,100 clinical cases of WNV
lance efforts for the past three years
other arboviruses, however. A total
infection including over 170 deaths to detect and respond to the WNV.
of 28 mosquito pools tested posiwere reported in the United States.
Health officials have established a
tive: 14 for St. Louis encephalitis
Human cases were reported in 37
surveillance network in all 15
(SLE) virus (Yuma, Maricopa, Pima
states.
counties. As of October 9, 2002,
and Pinal counties), and 14 for
This new mosquito-borne virus
the Arizona State Health Laboratory
western equine encephalitis (WEE)
spread across the country at an
(ASHL) tested over 600 mosquito
virus (Yuma, Pinal, Maricopa and
unprecedented rate in 2002.
pools, 1,200 sentinel chicken
Mohave counties). Twenty-seven
Evidence of WNV activity (laborablood
samples,
and
100
human
sentinel chickens seroconverted to
tory positive birds, mosquito samspecimens (serum and/or CSF). All
arboviruses, 16 to SLE (Yuma,
ples, sentinel chicken bloods, horswere negative for WNV except for
es and/or human cases) has been
the aforementioned humans and
found in 43 states.
Continued on page 8
Arizona is one of only five
among the 48 contiguous
Transmission Cycle of West Nile Virus
states that has not yet
documented in-state
WNV activity. However,
WNV was identified as
the cause of meningitis in
Bird to Mosquito
three Arizona residents
with travel/exposure
Accidental Hosts:
histories in other states:
People & Animals
Indiana, Missouri,
Michigan, and Ohio.
Insect Vector:
WNV infection was also
Mosquito to Bird
Mosquitoes
Reservoir Host:
confirmed in a horse in
Birds
Pima County with an
exposure history in
Minnesota.

Visit the ADHS Web site at www.hs.state.az.us
Cases of Valley
Fever Continue
to Rise
Page 2
November/December 2002

Norwalk-Like
Viruses
Page 3

Changes In Vital
Statistics Data
Collection
Page 4 & 5

Neonatal Meningitis
Prevention
Guidelines
Page 6

Summary Chart
of Reportable
Diseases
Page 7
Prevention Bulletin

1

Cases of Valley Fever Continue to Rise
By Ken K. Komatsu, M.P.H.

Figure 1

Reports of coccidioidomycosis
continue to increase in Arizona. In
2001 there were 2,301 reported
cases (43.4 cases per 100,000 population) and 2,294 reported cases
as of October 1, 2002. This would
project to a total of 3,059 cases in
2002 (Figure 1).
Seventy-five percent of the cases
occurred in Maricopa County (53.9
per 100,000), which exceed the
rates for Pinal and Pima County for
the first time in 10 years (Figure 2).
Demographic characteristics of
persons reported with coccidioidomycosis disease have
remained fairly stable. Persons over
65 years of age had double the rate
(83.6 per 100,000) compared to
those between ages 20 and 44
(42.6 per 100,000). During 2001,
Males were 1.4 times more likely
than females to be reported with
coccidioidomycosis (Figure 3).
Rates in 2001 for all races were
comparable with the exception of
Native Americans who were 50%
less likely to be reported with coccidioidomycosis than Whites.
Seasonal spikes in incidence of
coccidioidomycosis continue to be
noted between May and July and
between November and December.
Immigration of susceptible residents, a growing immunosuppressed population, changing climatic conditions affecting
Coccidioides immitis growth and
sporulation, construction and
development of previously undisturbed desert lands, and better
reporting may all have contributed
to the increase in reported cases.
In response, the Arizona
Department of Health Services has
enlisted the aid of the Centers for
Disease Control and Prevention to
assess the morbidity associated
with increased reporting of coccidioidomycosis, identify environmen-

3500
3000
2500
2000
1500
1000
500
0

*
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Year of Report

* Projected Figure

Figure 2

Coccidioidomycosis
in Arizona, 2001

Based on the earliest data
present. (Onset, Diagnosis
or Report) and (estimates
from) 2000 Census data

Key:
Counties Reported Cases
Rate per 100,000

Figure 2

Continued on page 6
2

Prevention Bulletin

November/December 2002

Norwalk-Like Viruses –
Common Cause of Gastroenteritis Outbreaks
By Cheryl McRill, M.D., Victor Waddell, Ph. D., and William Slanta

Norwalk-Like Viruses (NLV)
cause approximately 23 million
cases of gastroenteritis each year
and account for 96% of all nonbacterial gastroenteritis outbreaks
according to data from the Centers
for Disease Control and Prevention
(CDC).
NLV were recently associated
with an outbreak of diarrheal illness among river rafters in the
Grand Canyon, gastroenteritis
among participants in a Phoenix
youth golf tournament, several
nosocomial outbreaks of gastroenteritis in hospitals in the United
Kingdom, and two consecutive
Alaskan cruises on the same ship in
which 13-14% of passengers on
each cruise developed vomiting
and/or diarrhea. Each of these outbreaks was dramatic and highly
publicized, but outbreaks of gastroenteritis due to NLV are quite
common and often go unrecognized.
NLV viruses are a group of
related viruses named for the
group’s prototype which was identified as the cause of an outbreak of
gastroenteritis in Norwalk, Ohio in
1972. Previously referred to as
“small, round-structured viruses”
for their electron microscope
appearance, they are now placed
in the viral family Caliciviridae.
Serologic studies have shown that
antibodies to this viral group are
likely to be acquired in early childhood and seropositivity may range
from 50-90% in older children and
adults. Unfortunately, antibodies do
not provide long-lasting protection
from recurrent infection.

Clinical Presentation
Sometimes called “stomach flu”
or “winter vomiting disease,” the
illness caused by NLV actually
occurs year-round. It is self-limited
and brief, lasting only 2-3 days.
November/December 2002

Serious illness is unusual, although
vomiting and diarrhea may be profuse. Either vomiting or diarrhea
may be present alone, but usually
both occur together.

Physicians can play
an important role in public
health by suspecting
NLV when the clinical
presentation is compatible.
Other symptoms sometimes
seen include myalgia, malaise,
headache, and low-grade fever.
Onset may be either abrupt or
gradual after an incubation period
which is usually 1-2 days (range 18
to 72 hours). Stools are nonbloody, not mucousy, and do not
contain fecal leukocytes. The
peripheral white blood cell count is
usually normal or slightly elevated.
Other clinical laboratory tests are
non-contributory. Diagnosis may
be made by demonstrating a rising
titer between acute and convalescent serologies, but more often it is
based on the clinical course and
exclusion of other etiologies. As
with other viral gastroenteritides,
treatment is supportive to prevent
dehydration.
There is no vaccine or specific
treatment.

Low Infectious Dose
NLV is highly contagious with
an infectious dose estimated at less
than 100 virons and may be shed
in stools up to two weeks after resolution of symptoms. Not surprisingly, outbreaks of NLV gastroenteritis have been related to food
and water contaminated by ill or
post-recovery food handlers.
Contaminated drinking water
and ice was suspected as the

source of the recent gastroenteritis
outbreak among young golfers in
Phoenix. Raw shellfish harvested
from waters contaminated with
NLV have been a source of gastroenteritis outbreaks. NLV infection may also be transmitted
through person-to-person contact,
fomites, and possibly even the
aerosol route if the virus becomes
aerosolized through vigorous vomiting. Secondary attack rates
among contacts are high.
Physicians can play an important role in public health by suspecting NLV when the clinical
presentation is compatible. If a
food or waterborne outbreak is suspected, please contact your local
health department. Epidemiologic
investigation is the best way to
identify a source so that effective
outbreak control measures can be
taken and future cases prevented.
The best prevention measures are
hand-washing and strict hygiene in
food and water handling.

Laboratory Testing for NLV
Public health scientists at the
State Laboratory are developing a
reverse transcription-polymerase
chain reaction (RT-PCR) testing procedure for the detection of NLV
that is based on protocols provided
by the CDC. However, because
NLV is actually a group of genetically and antigenically diverse
viruses, cross-reaction with other
viruses may occur during RT-PCR
testing and, consequently, all positive results must be confirmed by
DNA sequencing.
Samples that test positive by RTPCR will be forwarded to the CDC
for confirmation by a combination
of electron microscopy, liquid
hybridization followed by DNA
sequencing and phylogenetic
Continued on page 4
Prevention Bulletin

3

Changes In Vital Statistics Data Collection
Beginning with the 2000 data
year in Arizona (1999 nationally)
two major changes have occurred
that affect the computation of mortality rates, tabulation of leading
causes of death and analyses of
mortality data over time.
First, a new revision of the
International Classification of
Diseases (ICD), used to classify
causes of death, was implemented.
The Tenth Revision (ICD-10) has
replaced the Ninth Revision (ICD9), which was in effect since 1979.
Second, a new population standard for the age adjustment of
mortality rates has replaced the
standard based on the 1940 population and used since 1943.
Both changes have profound
effects on the comparability of
mortality data and continuity in
statistical trends. Age-adjusted
rates can only be compared to
other age-adjusted rates that use
the same population standard.
Changing the standard has affected

the magnitude of age-adjusted
death rates. For example, in 2001,
the Arizona age-adjusted death
rate for cardiovascular disease
based on the 1940 standard was

The age-adjusted death
rate based on the year
2000 standard was
73 percent greater than
that based on the
1940 standard.
154.6 deaths per 100,000 population. The age-adjusted death rate
based on the year 2000 standard
was 267.3/100,000, 73 percent
greater than that based on the
1940 standard. The age-adjusted
rates based on the year 2000 population standard are larger because
the new standard reflects an older
age structure and it gives more
weight than the 1940 standard to
death rates at older ages where
mortality is higher.

Breaks in comparability of
mortality statistics effective with
deaths occurring in 2000 and later
also result from the implementation of ICD-10. ICD-10 is far more
detailed than ICD-9, with about
8,000 categories compared with
about 5,000 categories.
Any comparison of causes of
mortality in Arizona between 2000
and previous years needs to take
into account the changes in statistical trends that can be attributed to
changes in the classification system alone. In order to assess
whether changes in causes of
death are “real” or due to new
coding and classification procedures, “comparability-modified”
mortality rates are used for some of
the leading causes of death.
For more information on ICD10 code revisions, contact
Christopher Mrela at 602.542.2955
or cmrela@hs.state.az.us.
See Tables on Page 5

Norwalk Like Viruses – Continued from page 3

analyses to detect and characterize
NLV strain types. It is anticipated
that RT-PCR testing for NLV by the
State Laboratory will be implemented by the end of the year.
Confirmation of NLV positive samples by sequence detection and
genetic analyses will be offered at
the State Laboratory at a later date.
Submission of samples to the
Arizona State Laboratory for NLV
testing should be discussed with
State infectious diseases epidemiologists at 602.230.5932 before
they are sent to the lab.
Laboratory samples, including
stool and vomitus, should be collected in clean sterile containers
and shipped immediately at 4°C

(on cool packs). Approximately
5.0–10.0 gm or 5.0–10.0 mL (if
liquid) of sample are required to
perform the laboratory test. NLV
may be identified in stool specimens by RT-PCR for up to 2 weeks
after illness. In outbreak settings,
your local health department may
request stool specimens for PCR
testing as part of an epidemiologic
investigation. Turn around time for
the RT-PCR screen is expected to
take 72 hours. Reports will be
mailed to submitting agencies.
Positive results will be phoned in
to the submitting agencies and the
Bureau of Epidemiology and
Disease Control for outbreak
investigation.

Questions regarding submission of specimens for testing may
be called in to the Virology Section
of the Arizona State Laboratory at
602.542.6134.
Ref: “Norwalk Virus and Other
Caliciviruses,” Mandell, Douglas,and
Bennett’s Principles and Practice of
Infectious Diseases, 5th ed., 2000,
Churchill Livingston.
Cheryl McRill, M.D., is Medical Director at the
Bureau of Epidemiology and Disease Control
and can be reached at 602.230.5808 or
cmcrill@hs.state.az.us . Victor Waddell, Ph.D.,
and William Slanta are with the Arizona State
Health Laboratory and can be reached at
602.542.6134 or vwaddel@hs.state.az.us or
wslanta@hs.state.az.us, respectively.

Norwalk-Like Viruses (NLV) cause approximately
23 million cases of gastroenteritis each year
4

Prevention Bulletin

November/December 2002

Twelve Leading Causes of Death Among Arizona Residents in 2001
Based on Number of Deaths
The leading cause of death to Arizona
residents in 2001 continued to be heart
disease, which accounted for 10,312 or
25.2 percent of all. Cancer remained
the second most frequent cause of
death to residents of the state, being
responsible for 21.8 percent of all
deaths in 2001. Deaths due to chronic
lower respiratory diseases (a title
change from ICD-9 title chronic
obstructive pulmonary disease) ranked
third in 2001, with 2,463 resident
deaths reported. In 2001, chronic lower
respiratory diseases accounted for 6
percent of all deaths. The fourth leading
cause of death, accidents (unintentional
injuries), accounted for 2,430 or 5.9
percent of total deaths. Deaths due to
cerebrovascular disease ranked fifth in
2001, with 2,416 resident deaths
reported. Together, these five causes
accounted for 65 percent of total deaths
in 2001.

Based on Age-Adjusted
Mortality Rates
Because the age pattern of mortality
varies greatly by cause of death,
changes in crude death rates over time
can be influenced by the changing
composition of the population. In contrast, age-adjusted death rates eliminate
the influence of such shifts in the population age structure. Therefore, ageadjusted death rates are better indicators than crude rates for showing
changes in mortality risk over time and
among causes of death. Beginning with
the 2000 report, all age-adjusted mortality rates use the estimated year 2000
population as a standard. In order to
provide continuity and ease of interpretation, all age-adjusted mortality rates
for years before 2000 have been re-calculated using the year 2000 standard
population.

* Number of deaths per 100,000 population age-adjusted to the 2000 U.S. standard.

The age-adjusted mortality rates for five
of the 12 leading causes of death
showed an increase from 2000 to 2001:
accidents, Alzheimer’s disease, diabetes, nephritis, and assault (homicide).

Note: the cause-of-death titles are according to the Tenth Revision of the International Classification of
Diseases (ICD-10).

November/December 2002

Prevention Bulletin

5

Neonatal Meningitis Prevention
Guidelines Revised
By Clare M. Kioski, M.P.H.

Group B Streptococcus (GBS)
remains the leading cause of serious
neonatal infection despite great
progress in perinatal GBS disease
prevention in the 1990s.
Approximately 10% to 30% of pregnant women are colonized with
GBS in the vagina or rectum. In
Arizona, invasive Group B
Streptococcus has been reportable
since April 1997. There were 55
cases (0.7 per 1000 live births)
reported in 2001 (Table 1) of which
21% were Hispanic.
Data collected after publication
of the 1996 guidelines for the prevention of perinatal Group B streptococcal disease prompted reevaluation of prevention strategies. Some
of the key changes in the 2002
guidelines are:
• Recommendations of universal
prenatal screening for vaginal
and rectal colonization of ALL
pregnant women at 35-37 week’s
gestation;
• Detailed instruction on prenatal
specimen collection (vaginal-rectal swabs) and expanded methods of GBS culture processing;

• Updated prophylaxis regimens for
women with penicillin allergy;
• Recommendations against routine intrapartum antibiotic prophylaxis for GBS colonized
women undergoing planned
cesarean deliveries who have not
begun labor or had rupture of
membranes;
• A suggested algorithm for management of patients with threatened preterm delivery; and
• An updated algorithm for management of newborns exposed to
intrapartum antibiotic prophylaxis.
The 2002 guidelines and tools to
help promote prevention and educate providers and parents of infants
with early-onset GBS disease are
available at www.cdc.gov/groupbstrep.
Adapted from: Centers for Disease Control
and Prevention, Prevention of Perinatal
Group B Streptococcal Disease. MMWR
2002;51(No. RR-11): 1-22.
Clare Kioski is an epidemiologist with the Office
of Infectious Disease Services and
can be reached at 602.230.5932 or
ckioski@hs.state.az.us.
Figure 1

6

Prevention Bulletin

Valley Fever
Continued from page 2

tal and demographic factors associated with the increase, evaluate
the surveillance system for coccidioidomycosis, and attempt to
identify measures that may help in
preventing further disease.
Findings and conclusions from
this investigation will be shared in
a later issue.
Diagnosis of primary coccidioidomycosis will aid in diagnosis
of future cocci-related complications, rule out other causes and
ease the patient’s anxiety with a
diagnosis.
Clinical consultation for coccidioidomycosis is available
through the Valley Fever Center
for Excellence (http://www.arl.arizona.edu.vfce) at 1-520-6294700. Coccidioidomycosis is
reportable under A.A.C. R9-6-301.
Ken Komatsu, M.P.H., is Epidemiology
Program Manager, Office of Infectious
Diseases. He can be reached at 602.230.5932
or kkomats@hs.state.az.us.

Check us out
on the Web!
Visit the Arizona Department
of Health Services Website at
www.hs.state.az.us to view
or download an Acrobat PDF
version of new or past issues of
Prevention bulletin.

November/December 2002

SUMMARY OF SELECTED REPORTABLE DISEASES
(January - September, 2002)1
Jan - Sept
2002

Jan - Sept
2001

5 Year Median
Jan - Sept

3 (1)
0
1
45 (30)
0 (0)

8 (4)
1
2
328 (135)
0 (0)

6 (3)
1
4
59 (36)
1 (0)

531
33
12
479
300

495
25
6
507
320

420
30
9
569
387

254
188
758
3
3424

319
123
1104
9
2665

554
148
*
17
*

576
217
19
23

627
135
42
16

510
142
25
37

11218
2759
148 (11)

10868
2968
117 (21)

9391
3036
148 (20)

8 (0)
674

8 (1)
522

8 (1)
593

1
0
117

1
0
114

3
1
61

2314
157
381
412
223 (200)
1

1243
158
418
404
178 (154)
13

1243
158
336
404
321 (184)
13

VACCINE PREVENTABLE DISEASES:
Haemophilus influenzae, serotype b invasive disease (<5 years of age)
Measles
Mumps
Pertussis (<12 years of age)
Rubella (Congenital Rubella Syndrome)
FOODBORNE DISEASES:
Campylobacteriosis
E.coli O157:H7
Listeriosis
Salmonellosis
Shigellosis
VIRAL HEPATITIDES:
Hepatitis A
Hepatitis B
Hepatitis B: non-acute2
Hepatitis C
Hepatitis C: non-acute2
INVASIVE DISEASES:
Streptococcus pneumoniae
Streptococcus Group A
Streptococcus Group B in infants <30 days of age
Meningococcal Infection
SEXUALLY TRANSMITTED DISEASES:
Chlamydia
Gonorrhea
P/S Syphilis (Congenital Syphilis)
DRUG-RESISTANT BACTERIA:
TB isolates resistant to at least INH (resistant to at least INH & Rifampin)
Vancomycin resistant Enterococci isolates
VECTOR-BORNE & ZOONOTIC DISEASES:
Hantavirus Pulmonary Syndrome
Plague
Animals with Rabies
ALSO OF INTEREST IN ARIZONA:
Coccidioidomycosis
Tuberculosis
HIV
AIDS
Lead Poisoning (<16 years of age)
Pesticide Poisoning3
1
2
*
3

Data are provisional and reflect case reports during this period except Lead Poisoning which is by date of diagnosis.
These counts reflect the year reported or tested and not the date infected.
Case counts for non-acute Hepatitis B and C are not available before 1998.
Not all reports will be confirmed as meeting the case definition for pesticide poisoning upon further investigation.

November/December 2002

Prevention Bulletin

7

❍ Change of Address/Name
❍ Delete my name from your mailing list
❍ I received more than one copy
Please include your mailing label with all requests
for changes. Fax changes to 602.230.5959

PRSRT STD
US Postage
PAID
Phoenix, AZ
Permit No. 957

Arizona Department of Health Services
Public Information Office
3815 North Black Canyon Hwy.
Phoenix, AZ 85015
602.230.5901 • Fax 602.230.5959
Jane Dee Hull, Governor
Catherine R. Eden, Ph.D., Director ADHS
Lee A. Bland, Chief, Bureau of Epidemiology
and Disease Control Services
Editorial Board
Victorio Vaz, D.V.M., Ph.D., Acting State Epidemiologist
Tim Flood, M.D.
Kathy Fredrickson, M.P.H.
Will Humble, M.P.H.
Ken Komatsu, M.P.H.
Cheryl McRill, M.D.
Wesley Press, M.S.
Emma N. Viera, M.P.H.
Managing Editor: Courtney Casillas
e-mail: ccasill@hs.state.az.us
Contributors: Ken Komatsu, Clare Kioski, Craig Levy,
Christopher Marela, Cheryl McRill, William Slanta, Victor Waddell
This publication is supported by the Preventive Health and Health Services Block
Grant from the Centers for Disease Control and Prevention (CDC).
Its contents do not necessarily represent the views of the CDC.
If you need this publication in alternative format, please contact the ADHS Public
Information Office at 602.230.5901 or 1.800.367.8939 (State TDD/TTY Relay).

West Nile Virus – Continued from page 1

Maricopa and Pima
counties), and 15 to
WEE (Yuma and
Maricopa counties).
Additionally, one
horse with neurologic illness tested positive for WEE
in Cochise County. County vector
control personnel stepped-up
mosquito control efforts in the
affected areas.
The WNV morbidity and mortality nationwide in 2002 resulted
in dramatic increases in requests
for laboratory testing for WNV
across the country. Virtually all
state health laboratories and the
Centers for Disease Control and
Prevention (CDC) were swamped
with specimens. As a result,
many states, including the ASHL,
have established submission criteria for WNV testing (see below).
The ASHL performs an IgM
Capture ELISA (enzyme linked
8

Prevention Bulletin

immunosorbent assay) for WNV,
and Complement Fixation (CF)
for other arboviruses, including
SLE, WEE, EEE (eastern equine
encephalitis) and VEE (Venezuelan
equine encephalitis). Serologic
testing can be performed on
serum or CSF. Blood can be collected in a red top tube or serum
separator. Please consult with
your local health department epidemiology staff prior to submitting
specimens for testing to:
Arizona State Health Laboratory
Attn: Serology/Arbovirus Testing
1520 West Adams
Phoenix, Arizona 85007
The ASHL is providing
arbovirus testing (including WNV)
for all cases of encephalitis, and
hospitalized cases of aseptic
meningitis (especially in adults)
that occur from May through
November.

Please Note: most arbovirus
related illnesses tend to occur
during the summer and fall as this
corresponds with peak arbovirus
activity in mosquito populations.
The following information must
be submitted with all specimens:
patient name, date of birth, onset
date, specimen collection date,
symptoms/diagnosis, and any significant travel history prior to
onset. Lack of pertinent information may delay testing. Priority
will be given to hospitalized
cases. A number of commercial
laboratories also offer WNV testing. Please promptly report WNV
positive results to your local
health officials.

Craig Levy is the manager of the VectorBorne and Zoonotic Disease Section at the
Bureau of Epidemiology and Disease Control.
He can be reached at 602.230.5918 or
clevy@hs.state.az.us.

November/December 2002