Georgia epidemiology report, Vol. 18, no. 5 (May 2002)

May 2002

volume 18 number 05

Division of Public Health http://health.state.ga.us
Kathleen E. Toomey, M.D., M.P.H. Director
State Health Officer
Epidemiology Branch http://health.state.ga.us/epi
Paul A. Blake, M.D., M.P.H. Director
State Epidemiologist
Mel Ralston Public Health Advisor
Georgia Epidemiology Report Editorial Board
Carol A. Hoban, M.S., M.P.H. - Editor Kathryn E. Arnold, M.D. Paul A. Blake, M.D., M.P.H.
Susan Lance-Parker, D.V.M., Ph.D. Kathleen E. Toomey, M.D., M.P.H.
Angela Alexander - Mailing List Jimmy Clanton, Jr. - Graphic Designer
Georgia Department of Human Resources
Division of Public Health Epidemiology Branch Two Peachtree St., N.W. Atlanta, GA 30303-3186 Phone: (404) 657-2588 Fax: (404) 657-7517
Please send comments to: Gaepinfo@dhr.state.ga.us
The Georgia Epidemiology Report is a publication of the Epidemiology Branch,
Division of Public Health, Georgia Department of Human Resources

EPIDEMIOLOGY OF MALARIA IN
GEORGIA
While most cases of malaria reported in the U.S. occur among immigrants from and travelers to malaria-endemic areas of the world, some cases are acquired in the U.S. Probable autochthonous malaria transmission (local transmission without travel) has been documented in the past two decades in California, New York, New Jersey, Michigan, Texas, Florida, and Georgia.
Two episodes of probable autochthonous malaria occurred in South Georgia
within 20 miles of each other during 1996 and 1999. Both patients were diagnosed with P. vivax malaria, neither had a history of recent travel to a malaria-endemic area, and neither reported risk factors for induced malaria such as blood transfusion or injection drug use. Factors that potentially contributed to these locally-acquired cases were: the existence of ideal breeding habitats for Anopheles mosquitoes, the presence of migrant farm laborers, some from Mexico and Central America, who might have been parasitemic (or infected) reservoirs of P. vivax infection for mosquitoes, and climatic conditions favorable to the completion of the reproductive cycle of the parasite in the mosquito.
In addition to these rare autochthonous cases, immigrants and travelers may carry malaria from endemic countries, resulting in illness diagnosed in Georgia. Malaria is a notifiable

Figure 1:

Malaria Cases Reported to the Georgia

Division of Public Health, 1992-2000.

60

Number of Cases

50

40

30

20

10

0 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year

disease in Georgia. From January 1, 1993 to December 31, 2000, 331 cases of malaria were reported to the GDPH. The number of cases reported per year ranged from 31 in 1993 to 57 in 1997 (Figure 1). It is likely that malaria is under-diagnosed and underreported in Georgia. The increase in reported cases from 1993 to 1997 is probably due to better surveillance, increased travel to malarious regions, and increased immigration to Georgia from malarious regions.
Table 2 shows the demographic characteristics of the 331 malaria cases that were reported in Georgia from 1993-2000. It is not always possible to distinguish between travelers and immigrants based on information provided on case report forms. Complete follow-up with cases is often difficult or impossible for reasons that include language barriers.
The majority of reported malaria cases in Georgia (61.6%) reside in metro-Atlanta. Blacks of all ages are diagnosed with malaria in Georgia, but only 2.7% of Whites with malaria are under the age of 20 (Table 3). This may reflect the occurrence of malaria among Black immigrants of all ages, and among travelers who are often White adults.

MALARIA FACTS

Agent: A parasite. Human disease is caused by four species of the genus Plasmodium: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. Mixed infections may occur.
Reservoir and Mode of Transmission: Humans are the only important reservoir of human malaria; there is no known zoonotic reservoir. Malaria is most often transmitted by the bite of an infected female Anopheles mosquito. Rarely, transmission may occur by blood transfusion, use of contaminated needles or syringes (as by injecting drug users), or congenitally from mother to fetus.
Occurrence: Malaria is endemic to many tropical and subtropical areas including countries of Asia, Africa, South America, and Central America. Endemic malaria no longer occurs in many temperate-zone countries (such as the United States) or in some areas of subtropical countries. An estimated 300-500 million new cases and more than 1 million deaths due to malaria occur each year. Malaria incidence is increasing due to limited mosquito control measures, mosquito resistance to insecticides, and parasite resistance to chloroquine. The Centers for Disease Control and Prevention (CDC) receives approximately 1200 reports of malaria diagnosed in the U.S. each year.
Symptoms: Malaria typically presents with fever, malaise, headache, shaking chills, sweats, and nausea. Fevers may be persistent or come and go depending on the species that causes the infection, but the classically described alternate-day or other periodic fevers are not always present. P. falciparum infections may also present with cough, diarrhea, and respiratory distress; severe cases may progress to jaundice, coagulation defects, shock, renal failure, liver failure, pulmonary edema, acute encephalopathy, coma, and death. Clinical presentation may be atypical for patients taking prophylactic treatment or those who are partially immune.

Diagnosis: Preliminary diagnosis may be based on symptoms and travel history, but should be confirmed by demonstration of malaria parasites in blood films. Diagnosis may require repeated examination of blood smears. Identification of the infecting species is clinically valuable because recommended treatment varies by species, as does likelihood of severe disease and drug-resistance (See Table 1).
Reporting: Malaria is a notifiable disease in Georgia and cases should be reported using a Georgia Notifiable Disease Report Form (form 3095) and a CDC Case Report Form. Both forms may be downloaded from the Georgia Division of Public Health (GDPH) website at http://health.state.ga.us. It is important to provide as much clinical and travel information as possible with case reports. If a case of autochthonous malaria occurs in Georgia, local healthcare providers will be alerted, public education will be intensified, and other control measures will be instituted as appropriate.
Prevention: Appropriate measures should be taken to avoid mosquito bites. Chloroquine or other antimalarial drugs should be administered 1 to 2 weeks before travel to a malarious area and continued for 4 weeks after returning. Current treatment and prophylaxis information may be obtained from the Centers for Disease Control and Prevention (CDC) via the Internet or fax (See Malaria Resources). Potential vaccines are being developed and tested.
Treatment: Prompt treatment, especially of P. falciparum infections, is important. Case fatality rates for untreated children and non-immune adults infected with P. falciparum can be 10-40% or higher. Furthermore, untreated or insufficiently treated patients with malaria may be a source of mosquito infection for 3 years or more with P. malariae, for 1 to 2 years with P. vivax, and for as long as 1 year with P. falciparum. Obtain current treatment and prophylaxis information from the CDC via Internet or fax (See Malaria Resources).

Table 1: Epidemiologic and clinical characteristics of Plasmodium species causing human malaria.

Plasmodium species P. falciparum

Geographic Distribution
Eastern Hemisphere: common in sub-Saharan Africa, SE Asia, India
Western Hemisphere: Haiti, Amazon region

Approximate Incubation1 7-14 days

Onset2/Fever Pattern
Acute, highly dangerous disease for persons without immunity Infects and damages mature and immature blood cells Tertian fever (48 hour periodicity) Often drug-resistant

Persistence/Relapse
One attack with recurring fevers. No dormant liver stage--no relapses once treated. Reoccurrence of symptoms indicates inadequate treatment or infection with a drug-resistant strain.

P. vivax P. malariae
P. ovale

Eastern Hemisphere: common in Indian subcontinent, Papua New Guinea, Indonesia, Solomon Islands, Central Asia
Western Hemisphere: common in Central and South America
Eastern Hemisphere: low frequency in many areas: Tropical Africa, Papua New Guinea, South and Southeast Asia, Mediterranean region
Western Hemisphere: low frequency in tropical and subtropical Americas
Eastern Hemisphere: Small foci in sub-Saharan Africa and Papua New Guinea
Western Hemisphere: Not endemic

8-14 days3 7-30 days 8-14 days

Typically subacute Infects only young blood cells Tertian fever (48 hour periodicity)

Relapse of infection may occur 6-10 months or more after initial infection, as a result of dormant phase in liver.

Typically mild Quartan fever (72 hour periodicity)
Typically subacute Infects only young blood cells Tertian fever (48 hour periodicity)

No dormant liver phase-- no relapses. Parasites may persist in blood for 30 years or more. Reappearance of symptoms indicates inadequate treatment or infection with a drugresistant strain.
Relapses may occur 6-10 months or more after initial infection, as a result of dormant phase in liver.

1When infected by blood transfusion the incubation period may depend upon the number of parasites infused. The incubation is usually short, but may range up to 2 months. Incomplete or inadequate drug prophylaxis or treatment may also result in a prolonged incubation period. 2Cyclic fevers are characteristic of malaria. Fevers occur near the time of red blood cell lysis as schizonts rupture to release new infectious merozoites. Although the parasite cycle is 48 hours in P. falciparum, continuous fevers with intermittent irregular spikes are more characteristic of P. falciparum infection than a regular 48-hour cycle, especially in patients with no immunity.
3Some strains, particularly from temperate areas, may have a protracted incubation of 8-10 months.
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Table 2: Demographic characteristics of

malaria cases reported in Georgia from

1993-2000 (n=331).

Demographics SEX
Male Female Unknown HEALTH DISTRICT Total Metro-Atlanta Marietta (3-1) Atlanta (3-2) Forest Park (3-3) Lawrenceville (3-4) Decatur (3-5) Total outside Metro-Atlanta Unknown Location RACE Black White Asian/Pacific Islander Other/Unknown

n (%)

211

(63.7)

101

(30.5)

19

(5.7)

204

(61.6)

36

(10.9)

66

(19.9)

10

(3.0)

24

(7.3)

68

(20.5)

63

(19.0)

64

(19.3)

93

(28.1)

36

(10.9)

14

(4.2)

188

(56.8)

Table 3: Age distribution of malaria cases reported in Georgia by Race (Black or White), 1993-2000.

RACE BY AGE < 20 years old Black (n=93) 41 (44%) White (n=36) 1 (2.7%)

> 20 years old 52 (55%) 35 (97%)

Figure 2: Malaria Cases by Plasmodium species: Georgia, 2000. Most malaria reported to GDPH during 2000 (n=47) was caused by P. falciparum (45%), followed by P. vivax (36%), P. ovale (4%) and P. malariae (2%).

Unknown 13%

P. ovale 4%

P. malariae 2%

P. falciparum 45%

appropriate health education messages should be developed to increase awareness of malaria and to enhance use of local medical
services.
No anti-malarial prophylactic regimen provides complete
protection. Prevention of mosquito bites should still be the first line of defense against malaria and other mosquito-transmitted diseases. Travelers to malarious areas should use personal mosquito repellent when mosquitoes are active and should use a pyrethroid-containing flying-insect spray in living and sleeping areas during evening and nighttime hours, unless rooms are wellscreened. If there are mosquitoes in the room, travelers should sleep under mosquito netting; bed nets sprayed with permethrin are more effective than untreated bed nets.
Even when not traveling, Georgia residents should be educated
about mosquito bite prevention and ways to reduce mosquitobreeding habitats around their homes (dump out standing water). The importance of having screens on windows and doors of homes should be emphasized
Travelers to malarious areas may require malaria
chemoprophylaxis starting 1 to 2 weeks before travel and continued for 4 weeks after return to the U.S. For details, please consult CDC recommendations (See Malaria Resources). Travelers should know the signs and symptoms of malaria and should seek immediate medical care if they become ill. Travelers might be advised to administer self-treatment if they become ill and medical care will not be available to them within 24 hours.
Malaria Resources:
For assistance in determining risk for malaria and for information about preventing and treating malaria, the Centers for Disease Control and Prevention (CDC) has two sources of information for healthcare providers:
The Travelers' Health website: http://www.cdc.gov/travel, OR Toll-Free Fax Information Service: call 1-888-232-3299 and listen to the instructions

REFERENCES:

P. vivax 36%
RECOMMENDATIONS FOR PREVENTION AND
CONTROL OF MALARIA IN GEORGIA AND FOR
TRAVELERS:
Malaria should be considered when evaluating febrile patients
with a history of travel to a malaria-endemic region. In addition, Georgia health care providers should be aware that local malaria transmission can occur in Georgia. Several factors enhance the possibility of malaria transmission to humans in Georgia: (1) Anopheles mosquitoes are present in Georgia and in some areas are abundant, (2) the climate in Georgia is conducive to malaria transmission because it allows female Anopheles mosquitoes to live long enough for the reproductive cycle of Plasmodium to be completed in the mosquito mid-gut, and for transmission to humans from the mosquito salivary gland, and (3) parasitemic (or infected) travelers or immigrants who are not promptly or properly treated can be a source of infection for mosquito vectors. Access to primary care services for immigrant and migrant worker populations in Georgia should be improved. Culturally

1. American Public Health Association. Malaria. In: Chin, J, ed. Control of Communicable Diseases Manual. 17th ed. United Book Press, MD; 2000: 310-323.
2. Centers for Disease Control and Prevention. Probable locally acquired mosquito-transmitted Plasmodium vivax infection--Georgia, 1996. MMWR 1997; 46: 264-267.
3. Centers for Disease Control and Prevention Division of Parasitic Disease website; http://www.cdc.gov/ncidod/dpd/parasites/ malaria/default.htm.
4. Krogstad, Donald J. Plasmodium Species (Malaria). In: Mandell GL, Bennett JE, and Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 5th ed. Churchill Livingston, PA; 2000: 2817-2831.
5. Zucker, JR. Changing patterns of autochthonous malaria transmission in the United States: A review of recent outbreaks. Emerging Infect Dis 1996; 2: 37-43.
Written by Catherine Rebmann, M.P.H.

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The Georgia Epidemiology Report Epidemiology Branch Two Peachtree St., NW Atlanta, GA 30303-3186

PRESORTED STANDARD U.S. POSTAGE
PAID ATLANTA, GA PERMIT NO. 4528

May 2002

Volume 18 Number 05

Reported Cases of Selected Notifiable Diseases in Georgia Profile* for February 2002

Selected Notifiable Diseases
Campylobacteriosis Chlamydia trachomatis Cryptosporidiosis E. coli O157:H7 Giardiasis Gonorrhea Haemophilus influenzae (invasive) Hepatitis A (acute) Hepatitis B (acute) Legionellosis Lyme Disease Meningococcal Disease (invasive) Mumps Pertussis Rubella Salmonellosis Shigellosis Syphilis - Primary Syphilis - Secondary Syphilis - Early Latent Syphilis - Other** Syphilis - Congenital Tuberculosis

Total Reported for Feb 2002
2002 23
2711 7 2 40
1245 6 50 15 0 0 1 0 2 0 37 36 4 15 36 30 0 19

Previous 3 Months Total

Ending in Feb

2000

2001 2002

98

105

87

6320

7772

8056

44

34

27

8

5

6

296

242

138

4122

4356

4377

24

32

37

58

145

140

57

116

73

1

2

1

0

0

0

28

21

11

1

2

0

20

5

2

0

0

0

279

252

246

67

75

326

31

24

18

76

60

43

141

131

149

176

192

119

5

6

0

168

192

148

Previous 12 Months Total

Ending in Feb

2000

2001 2002

665

622

616

30218

30254

32738

164

182

154

43

45

48

1345

1170

902

20974

19435

18169

83

86

111

432

438

924

242

390

399

6

11

10

0

0

0

76

52

45

5

3

7

63

39

23

0

1

0

1934

1694

1701

283

331

855

143

119

85

282

277

273

615

540

635

752

744

750

19

21

15

650

690

531

* The cumulative numbers in the above table reflect the date the disease was first diagnosed rather than the date the report was received at the state office, and therefore are subject to change over time due to late reporting. The 3 month delay in the disease profile for a given month is designed to minimize any changes that may occur. This method of summarizing data is expected to provide a better overall measure of disease trends and patterns in Georgia.
** Other syphilis includes latent (unknown duration), late latent, late with symptomatic manifestations, and neurosyphilis.

Report Period
Latest 12 Months: 04/01-03/02 Five Years Ago: 03/97-02/98 Cumulative: 07/81-03/02

Total Cases Reported* <13yrs >=13yrs Total

Percent Female

AIDS Profile Update
Risk Group Distribution (%) MSM IDU MSM&IDU HS Blood

Unknown

2

1970

1972

24.3

36.6

8.5

2.6

12.3

2.0

38.0

4

1505

1509

21.3

40.7

20.1

4.5

19.7

1.2

13.8

210

24554 24764

17.4

47.9

17.7

5.5

13.3

1.9

13.7

MSM - Men having sex with men

IDU - Injection drug users

HS - Heterosexual

* Case totals are accumulated by date of report to the Epidemiology Section

- 4 -

Race Distribution (%) White Black Other

19.4 75.7

4.9

22.8 74.5

2.7

34.5 63.2

2.4