Spotted fever group rickettsiae in Dermacentor variabilis from Cape Cod, Massachusetts.

Spotted fever group (SFG) rickettsiae were identified by indirect immunofluorescent antibody tests in 1.1% of 6,956 specimens of Dermacentor variabilis collected on Cape Cod, Massachusetts. Forty-one of 45 rickettsial isolates were serotyped as Rickettsia montana, one as Rickettsia rickettsii, and three were unidentified. Studies of canines and humans with clinical evidence of spotted fever, and of healthy dogs with antibody to SFG rickettsiae, indicated that exposure of the canine population to R. montana was common but that R. montana was not involved in the etiology of spotted fever.

Natural infection of dogs on Cape Cod with Rickettsia rickettsii.

Four isolates of rickettsiae from sick dogs on Cape Cod, Mass., were serologically identical to isolates of Rickettsia rickettsii from human patients with Rocky Mountain spotted fever. The antigenic analysis used the indirect fluorescent-antibody test and antisera prepared in mice to each of the isolates and to reference strains of R. rickettsii and Rickettsia montana. Serological responses of infected dogs were specific for R. rickettsii, although antibodies to R. montana were also detected in the sera of most of the canines.

Use of enteric vaccines in protection against chlamydial infections of the genital tract and the eye of guinea pigs.

Guinea pigs in a test group were fed living guinea pig inclusion conjunctivitis (GPIC) organisms classified as Chlamydia psittaci in 60% yolk-sac suspensions as enteric vaccines, while animals in a control group received uninfected yolk sac. Seven test animals and 14 control animals were challenged 11 or 22 days later with 1,000 50% infectious doses of GPIC organisms in either the conjunctiva or the vagina. Evidence of protection from mucosal infection in both sites was noted in test animals. Clinically, the disease was less severe, and microbiologically, lower percentages of mucosal cells were infected. The results suggest that enteric vaccination against mucosal infections of the eye and the genital tract with chlamydial agents is possible.

Immunity to chlamydial infections of the eye. IV. Immunity in owl monkeys to reinfection with trachoma.

In a study of trachoma in owl monkeys, it was found that owl monkeys are equally susceptible to low and high doses of trachoma and that resistance to reinfection persisted for six months in the majority of animals. Previous infections with a single trachoma type did not elicit greater resistance than previous infections with two types. Both serum antibodies and eye secretion titers correlated well with resistance to reinfection, but it is not as yet clear if either or both play a substantial role in immunity to trachoma.

An indirect immunofluorescent test for human antibodies to tetanus toxoid using an insoluble toxoid as antigen.

An indirect fluorescent antibody (FA) test for detection of human antibodies to tetanus toxoid is described using an ethylchloroformate-prepared polymer of tetanus toxoid as the particulate slide test antigen. Titres of the FA test were compared with those obtained with the toxin neutralization (TN) test in mice. No antisera were FA-positive at less than 0-0025 AU/ml. Positive correlation of the FA test with the TN test was 50% between 0-0025 and 0-01 antitoxin units/ml (AU/ml) and 100% between 0-02 and 160 AU/ml. In general, an increase in FA titres correlated with an increase in TN titres beginning at about 0-08-0-16 AU/ml.

Virulence of Rickettsia prowazeki for head lice.

Wild head lice were obtained by combing out adult and instar lice from the uncut hair of school children. Normal body lice were selected from a colony of rabbit-adapted body lice obtained from the United States Department of Agriculture and maintained in the Department of Microbiology for more than 10 yr. Thirty-nine head lice and 60 body lice were fed on a rabbit that had been injected intravenously with a 10% suspension of a yolk sac pool from eggs heavily infected with the Ankara strain of virulent R. prowazeki. Five days after infection, 33 body lice and 16 head lice had survived and were feeding on a volunteer. Between Days 5 and 9, 13 head lice were dead or moribund and all of them were positive by IF for R. prowazeki. The three surviving head lice were also positive. Tests on the 33 body lice showed that 22 were positive for R. prowazeki, including four of the five body lice that survived until Day 15. In summary, head lice can be readily infected with R. prowazeki and disseminate virulent R. prowazeki organisms in their feces. Thus, theoretically, head lice appear to be highly potential as transmitters of R. prowazeki under optimal epidemiologic circumstances.

Rickettsiae and rickettsial diseases.

This paper summarizes present knowledge on rickettsiae and rickettsial diseases, and on their epidemiological characteristics, control, and public health significance. There are many natural foci of rickettsial diseases, from where the disease may spread to other areas in the world under changing socioeconomic conditions. Because of rapid long-distance travel, sporadic cases of serious rickettsial diseases may today appear far from endemic areas where the infection occurred. Even in endemic areas the disease may be misdiagnosed and deaths may occur as a result of inadequate treatment. Rapid treatment of rickettsial infections (preferably with tetracyclines) is therefore most important. Epidemic louse-borne typhus, though no longer subject to the International Health Regulations, remains one of the diseases in the WHO epidemiological surveillance programme. This disease continues to be a major cause of morbidity and mortality in some parts of Africa and it is present also in parts of the Americas and of Asia. Scrub typhus remains a continuing and serious public health problem in areas of South-East Asia and in the Western Pacific. The annual number of reported cases of Rocky Mountain spotted fever in the USA showed an increase during the last two decades, which may be due to improved recognition as well as to increased outdoor activities and migration of people from the city centres to the suburbs. Related forms of tick-borne typhus occur in South America, the Mediterranean region, Africa, South-East Asia, the Far East, and the Western Pacific. Increasing in number, though still sporadic, are reports of serious illness from chronic Q fever infection in many parts of the world.

Serum iron and haemoglobin levels in pregnant East African women of mixed tribal origin.

PIP: To clarify the pattern of hemoglobin and serum iron response during pregnancy, 187 pregnant women from 14 tribal groups in the Nairobi area were studied. None of the women had received iron medication prior to presenting at the antenatal clinic and all were in a good nutritional state. 25 females and 23 males admitted to the Kenya National Hospital for minor surgical procedures were used as controls. The general incidence of anemia among the study subjects was 8.5%, which is lower than that noted in other studies of iron deficiency during pregnancy. The incidence of anemia was higher among primigravidae (11.3%) than among women in the para 3-5 (4%) or para 6+ (1%) groups. This could be due to a high incidence of adolescent pregnancies among primigravidae with a double demand on iron stores. However, further analysis of the data indicated that mean hemoglobin concentrations did not significatnly differ by age. An alternative explanantion is that pregnancy represents the 1st time many women attend a clinic and may therefore be the 1st opportunity for a diagnosis of treatable anemia. Serum iron and total iron binding capacity levels were higher in male controls than in the nonpregnant female controls, who in turn had higher levels than the pregnant cases. Finally, the study subjects demonstrated a rise in total iron binding capacity and a slight fall in serum iron concentration with advancing pregnancy, a pattern that has been noted in other studies. These data suggest that iron deficiency anemia during pregnancy is not a significant problem in Nairobi and the prescription of iron should be based on individual requirements.^ieng

Rgulation of intestinal alkaline phosphatase levels in the rat. Role of the adrenal cortex.

Bilateral adrenalectomy produces a reduction in the alkaline phosphatase concentration in rat intestine, which is not prevented by the administration of saline, but is prevented by the administration of cortisone. The administration of A.C.T.H. to normal rats leads to a rise in intestinal alkaline phosphatase levels associated with a small increase in the weight of the adrenals, while the administration of hydrocortisone produces large increases in the enzyme, even with doses which cause significant hypoplasia of the adrenal glands. The significance of these findings in relation to mechanisms of fat absorption and the treatment of steatorrhoea is discussed.

The natural history of recrudescent typhus (Brill-Zinsser disease) in Bosnia.

Between 1954 and 1963, typhus, both epidemic and recrudescent, has been studied in Bosnia. The recrudescent typhus cases occur sporadically throughout the year, whereas epidemic typhus occurs mainly between November and June. During 1954-63, some 10-20 years after the extensive typhus epidemics of the Second World War, the highest incidence of recrudescent typhus was in the 20-50 year age-group, whereas epidemic typhus reached its highest incidence in the 2-30 year age-group. Field observations support Zinsser's hypothesis that man is the interepidemic reservoir of typhus. Recrudescent typhus is not likely to cause epidemics of primary epidemic typhus in environments where lice are scarce. However, if typhus is to be eradicated, it seems that it will be necessary to destroy all lice in areas where there are people who have at some time had the disease.