Current Trends

Influenza in the United States has decreased markedly, and there is no longer evidence of nationwide epidemic activity. Pneumonia and influenza (P and I) mortality from 121 cities has fallen below the epidemic threshold for the first time in 11 weeks (Figure 1). P and I mortality is at or below epidemic thresholds in all regions except the Pacific and West South Central regions.

Although preliminary and based on extrapolations for the entire country from deaths due to P and I in 121 cities, an estimated 11,000 P and I excess deaths can be attributed

to the A/Victoria epidemic this year. This is the highest number since the Hong Kong 1968-1969 epidemic, when ar estimated 12,700 P and I deaths occurred, according to the National Center for Health Statistics (1).

Reported by the Viral Diseases Div, Bur of Epidemiology, CDC.

Reference

1. Dowdle WR, Coleman MT, Gregg MB: Natural History of Influenza Type A in the United States, 1957-1972. Prog Med Virol 17:91-135, 1974

Two fatal cases of malaria were reported to CDC in 1975. One of these was also the only case of transfusioninduced malaria reported in the country in 1975. Case 1

On August 18, 1975, an 83-year-old woman was adImitted to a California hospital with a 1 week history of fever and chills. Physical examination was essentially normal but a peripheral blood smear revealed Plasmodium malariae. In spite of treatment with oral chloroquine phosphate, she developed confusion, nausea, vomiting, signs of congestive heart failure, and mild renal insufficiency and died on August 21. Postmortem examination failed to reveal any evidence of tissue damage related to her malarial infection.

The patient had no history of malaria exposure. However, on June 18 and 19, 1975, she had received 2 units of packed cells during and after surgery for carcinoma of the colon. Investigation of the 2 blood donors revealed elevated serologic titers to P. malariae in 1-a 33-year-old man who had spent much of his early childhood in Mexico but had not been out of the United States since age 6. He had no past history of blood transfusions or malaria. Blood smears were negative for malarial parasites. Case 2

An 8-year-old Cambodian child at the Fort Chaffee Refugee Center, Arkansas, was admitted to the infirmary on November 6, 1975, with nausea, vomiting, lethargy, and malaise. Peripheral blood smear on admission showed Plasmodium falciparum. The patient was treated with chloroquine but 36 hours after admission suddenly aspirated and died despite attempts at resuscitation. Postmortem examination revealed numerous parasitized erythrocytes within capillaries of the brain, heart, and other viscera.

The child had no past history of malaria although three months before her death she had had a febrile illness while

staying in a refugee camp in Thailand. Her symptoms resolved after an injection of an unknown medication. She arrived in the United States on October 19, 1975, and was well until shortly before her hospitalization.

Reported by L Davenport, MD, Ft. Smith, Ark; F Bussey, MD, W Faggett, MD, R Hodder, MD, U.S. Army, Fort Chaffee; AG Dean, MD, Acting State Epidemiologist, Arkansas State Board of Health; WR Metge, MD, RW Purvis, MD, Modesto (CA); RL Dubois, Delta Blood Bank, Modesto; FB Waldorf, MD, Turlock; RW Watson, MD, J Shaw, PHN, Stanislaus County Health Dept; RR Roberto, MD, California State Dept of Health; Parasitology Div, Bur of Laboratories, Field Services Div, Parasitic Diseases Br, Bacterial Diseases Div, Bur of Epidemiology, CDC.

Editorial Note: The P. malariae infection was probably a contributory factor in the death of patient 1; with patient 2, however, an overwhelming P. falciparum infection clearly caused death.

Between 1963 and 1974, 40 cases of transfusion-induced malaria were reported from the United States. Sixteen (40%) of these were due to P. vivax, 13 (32%) to P. falciparum, 10 (25%) to P. malariae, and 1 (3%) to a mixed infection. Since P. malariae was responsible for only 1.4% of malaria cases reported in the United States during the same period, it is proportionately the most important cause of transfusion-induced malaria.

Deaths from P. malariae infection are uncommon in this country-only 1 of the 51 malaria-related deaths reported between 1963 and 1974 was due to infection with this organism.

Because of the well-known tendency of P. malariae to cause prolonged, low-level, asymptomatic parasitemia, it is often impossible to identify organisms in donors' blood smears. Consequently, serologic testing for anti-malarial antibody plays an extremely important role in the investigation of febrile transfusion reactions.

Current Trends

1974 marks the first year on record that no cases of rabies in humans in the United States were reported. During the same period, 3,200 laboratory confirmed cases of rabies in animals were reported in the United States - 498 fewer cases than in 1973. All of the contiguous states and Alaska and Puerto Rico reported cases; Hawaii, the District of Columbia, Guam, and the Virgin Islands had no cases (Figure 1).

CDC has been keeping records on rabies in animals and humans since 1961, but records were kept by the U.S. Department of Agriculture beginning in 1938.

Seventy-nine percent (2,517) of the animal cases reported in 1974 were in wild animals. For the 14th consecutive year, skunks were reported to be the animals most frequently infected; they accounted for 45% of the total cases. The other animals most frequently infected by percentage of total cases were bats (17%), foxes (10%), cattle (8%), dogs (8%), raccoons (5%), and cats (4%).

A total of 683 cases of rabies in domestic animals were reported from 34 states and Puerto Rico. This was 84 fewer cases than in 1973, and a 19% decrease from the average annual total for the preceding 5 years. Rabies was found in 256 cattle, 248 dogs, 124 cats, 41 horses or mules, 8 sheep or goats, and 6 swine. In general, cases occurred in farm