The American Journal of Tropical Medicine and Hygiene - Volume 8, Issue 4, July 1959

A study in vitro was performed, testing 183 compounds against the filariform larvae of Ancylostoma braziliense.

As previous workers had found, the larvae are resistant to many commonly used parasiticides.

Among the organic phosphates, Co-ral (O,O-diethyl O-(3-chloro-4-methyl-7-coumarinyl) phosphorothioate) and malathion had activity which might be of practical value in the treatment of human infections and for application to contaminated soil. Dilan among the chlorinated hydrocarbons, chlorpromazine among the phenothiazines and Vapam® among the nematocides showed similar activity.

The importance of spontaneous cure of creeping eruption in the evaluation of drug therapy is discussed.

• 1.  Salmonella typhi and Shigella flexneri, introduced into CSMA, a normally contaminated larval medium, were recovered infrequently from larvae and not at all from adult houseflies.
• 2.  Under the same conditions, Salmonella paratyphi B was recovered more frequently from larvae and adults, though from a smaller percentage of adults than larvae.
• 3.  S. typhi, when introduced into a sterilised larval medium, probably underwent some multiplication, whether or not maggots were present.
• 4.  Each of the above species, including Salmonella enteritidis, when introduced into a sterilised larval medium, was routinely recovered from larvae and pupae of various ages. Mature maggots typically harbored about 107 organisms. The counts of pupae from the second day until emergence were stabilized at 103 to 104. A small number of pupae were sterile or retained relatively few bacteria.
• 5.  An explanation based on interspecific competition in the larval medium is suggested for the differential survival of these pathogens in fly stages breeding under natural conditions.

• 1.  Listed are species of bacteria, the so-called normal flora, which successfully survive metamorphosis and can be recovered from emerging adults breeding in the laboratory in CSMA, and under natural conditions in horse manure.
• 2.  The number of bacteria present in mature maggots, prepupae, pupae and emerging adults breeding in the laboratory in CSMA and under natural conditions in horse manure, privy contents and in garbage is presented in graphic form. Mature maggots support populations of 107 bacteria. During the prepupal stage, the count falls to 105 and 106. At the commencement of pupation counts generally range from 104 to 105, and this range is maintained during metamorphosis. The majority of emerging flies retain 102 or 103 bacteria, whereas some are sterile and others have 106. Thus two declines consistently appear in the survival pattern: in the prepupa and the newly emerged adult.
• 3.  Single-species infection with Shigella or Salmonella, dual infection and infection with a multiple saprophytic flora exhibit a pattern of bacterial survival which is essentially similar in all cases. On the basis of the evidence presented in this and the preceding study, it is considered doubtful that the normal flora are better suited than the pathogens for survival in the gut of the developing fly.

• 1.  A survey is reported of intestinal parasitism occurring in 69 Marshall Islanders exposed to radioactive fall-out four years previously. This is compared with parasitic infections occurring in 112 nonexposed Marshall Islanders.
• 2.  No significant difference was found between the two groups. The over-all rates for Entamoeba histolytica, Trichuris trichiura and hookworm were 18.2, 34.3 and 5.5 per cent, respectively. No other important parasitic pathogens were found. Infected individuals generally had low worm burdens and none of the amebiasis cases showed clinical symptoms attributable to this infection.

Examinations for the presence of neutralizing antibody to the Western equine encephalitis (WEE) and St. Louis encephalitis (SLE) viruses were made of blood specimens from parturient mothers residing in an endemic area of Western equine and St. Louis encephalitis. It was found that 11 per cent of the mothers studied possessed neutralizing antibody to the WEE virus and 27 per cent possessed neutralizing antibody to the SLE virus; there also was evidence of a direct relationship between the length of residence in the area and the acquisition of such antibody.

It was found that both complement-fixing and neutralizing antibodies to these two viruses readily pass the placenta, but no evidence was obtained that the difference between the proportion of infants possessing antibody to the WEE virus and those possessing antibody to the SLE virus is responsible for the remarkable difference in the attack rates of these two agents for infants. The temporal persistence of passively acquired neutralizing antibody to the WEE and SLE viruses appeared to be no greater than that reported for antibodies to other viral agents.

Pyrimethamine was used in two areas of Venezuela with partially refractory malaria where the vectors were Anopheles aquasalis and Anopheles nunez-tovari.

During the months of July through December, 1957, a total of 111,995 people received pyrimethamine once weekly at a dose of 50 mg to adults and correspondingly smaller doses to children. The above dosages were eminently effective in stopping transmission as evidenced by the fact that no parasite-positive cases were found during the last three months of the project. Relapses appeared in both areas, however, after drug administration was stopped which showed that pyrimethamine as employed here did not produce suppressive cure of all vivax infections. It is hoped that pyrimethamine given at the same dosage and continued for a greater length of time in areas of partially refractory malaria will interrupt transmission until the infections die out.

A syndrome that closely resembles hepatosplenic schistosomiasis in humans developed in mice following infection with Schistosoma mansoni. Data obtained from the infected mice suggest that the pathogenesis of the syndrome was related to the penetration of the portal canals of the liver by large numbers of schistosome eggs which incite granulomatous reactions and obstruction of portal blood flow. This in turn produces portal hypertension and the development of congestive hepato-splenomegaly, esophageal varices and ascites. Histologically there was little damage to the liver parenchyma, which is further borne out by very little liver function test derangement. A severe anemia developed in some of the infected mice (4 to 6 gm per cent hemoglobin).

Malaria surveillance data for 1956 and 1957 have been presented and discussed. Points worthy of particular note include the steady decline in morbidity to a very low yearly figure, the appearance of a few primary indigenous cases every year, the importance of the military population in the present pattern of introductions from foreign sources and the declining importance of Mexico as a source of malaria. Eradication, although near at hand, has not been achieved in this country. Eradication here appears to be dependent on at least much more effective control, if not eradication, of malaria elsewhere in the world. For the present, continuing individual case surveillance offers the best means of preventing flare-ups of malaria in the United States.

This paper is based on the comparative study of 15,516 specimens of Taphius glabratus from 36 localities and 12,776 of Taphius tenagophilus from 31 localities. A description of the renal region of both species is given, and it is concluded that they are distinguishable by the presence (in T. glabratus) or absence (in T. tenagophilus) of a ridge along the middle line of the membrane which covers ventrally the renal tube.

The ridge makes its appearance in specimens of about 10 mm in shell diameter and then gradually develops as the animal grows. It rises from a pigmented stripe which represents its forerunner in the small specimens under 10 mm in diameter.

The renal ridge is defined, both anatomically and histologically, and is shown to be a reliable diagnostic character of T. glabratus subject to age variation.

The unridged renal membrane of T. tenagophilus is also defined, with especial reference to its variation and to some unusual characteristics that may lead the taxonomist to confuse T. tenagophilus and T. glabratus.

The polarographic method for oxygen was applied to the problem of aerobiasis-anaerobiasis in echinococcosis to show that:

• 1.  The dissolved oxygen content of fluids of 3 hydatid cysts of the bovine lung ranged from 2.80 to 3.12 mm3 per ml, of 7 hydatid cysts of the bovine liver from 1.28 to 2.28 mm3 per ml.
• 2.  The Q O2 of hydatid scolices decreased with environmental oxygen tension until at a tension of 0.80 ± 0.48 mm3 per ml the rate became and remained zero.
• 3.  The polarographic Q O2 at an oxygen tension representing hydatid cyst fluid saturated with air (“optimum rate”) ranged from 0.39 to 1.50 (0.85 ± 0.39).
• 4.  The Q O2 at the in vivo oxygen tension of lung cysts was 96 per cent and of liver cysts 54 per cent of the mean “optimum rate.” It would appear therefore that hydatid scolices are able to carry on predominantly aerobic metabolism in vivo.
• 5.  Hydatid scolices possibly repay an accumulated oxygen debt following anaerobic incubation.

A newly recognized agent, named Uruma virus, was isolated from the blood of 2 febrile Okinawan colonists living in the rain forest of eastern Bolivia in March 1955. Studies of its physical properties, host range and immunological characteristics have been described.

The virus was consistently pathogenic to infant mice, embryonated eggs and several tissue cell lines, but only weakly pathogenic for weanling mice, adult guinea pigs, hamsters and rabbits. Its particle size was estimated, by filtration and ultracentrifugation, to be about 25 mµ. It was found to belong to Casals' Group A, to bear a close antigenic relationship to Mayaro virus and to be more distantly related to Semliki Forest and Sindbis viruses.

Antibody studies indicated that: (a) Uruma virus was the cause of illness in the patient from whom it was isolated, and (b) infection with the virus, or a close antigenic relative, is fairly common among indigenous residents of the rain forest adjacent to Santa Cruz, Bolivia.

Attempts to recover dengue virus from 5 acute phase human serum specimens which had been stored at CO2 icebox temperatures for a period of 12 years were carried out in hamster kidney cell cultures. The one successful isolation attempt yielded a type 2 dengue fever virus. The importance of the procedures used for increasing the probability of recovery of viruses from virus-containing materials was discussed.

Three years' experience in attempting to isolate viruses from conjunctival specimens from the autochthonous population of Eastern Saudi Arabia is described. From several thousand examinations, material for virus isolation was obtained from approximately 1000 individuals. Nine hundred forty-eight (948) specimens were tested in tissue culture and yielded two Coxsackie viruses, B1 and B2 and 65 adenovirus strains which fell into at least 13 different types. Of the 64 typed strains, the most common types were types 3, 8, 17 and strain BAR-2. Type 4 was isolated only three times and type 7 twice.

During the course of this study, several types of adenoviruses were isolated in Saudi Arabia which had not been encountered elsewhere. The new viruses are types 15, 16 and 17,9 and the strains designated 587, 931, 1645 and 2711, which have not been assigned type numbers as yet.

There was a marked seasonal incidence in the isolations of adenoviruses; 92 per cent of the 65 strains being obtained during the summer months of April through September. Only five strains were isolated from October through March, although more than half the specimens were obtained during this period. Despite the fact that over half the attempted isolations were in the age group 3 years and over, 81 per cent of the isolations came from children under 2 and 90 per cent from those under 3 years. No clear cut wide-spread epidemics due to types 3, 4 and 7, were encountered in this study of the agents recoverable from the conjunctivae of Saudi Arabs. Brief consideration is given to the possible role of adenovirus infection in the clinical complex which is diagnosed as trachoma in Eastern Saudi Arabia.

Five blind children were experimentally infected with adenoviruses type 16, 17 and strain “931,” and with conjunctival scrapings from 2 cases of trachoma. The clinical signs and symptoms and the course of illness were compatible with those of acute follicular conjunctivitis. Viruses were reisolated in 2 of the 3 cases infected by the adenoviruses while immunological response was detected in all 3 cases. Histological findings of biopsied materials taken during the acute inflammatory stage were similar for all 5 cases.

A total of over 2,300 animals principally of 20 species of pet animals, domesticated animals, wild rodents and birds were studied by means of the dye test for toxoplasmosis or by parasitological methods or both. The findings were as follows:

• 1.  Memphis cats were very frequently found infected with Toxoplasma judging by both the dye test and parasitological study. Rates were the highest for any species studied.
• 2.  Dogs showed a significant number of serologic positives and infections were demonstrable infrequently.
• 3.  Infections were also found in chickens, a pigeon and domesticated ducks but samples were insufficient to estimate general prevalence.
• 4.  A single swine infection was found, but serological results indicated infection was fairly frequent. Serological results on cattle, horses, mules and sheep were presented but lack of experimental knowledge precluded interpretation.
• 5.  Rats were found infected occasionally as were house mice. Six infected mice were found in a household in which a human case of toxoplasmosis had occurred.
• 6.  No infections were found in wild rodents or wild birds nor was there serological evidence of infection except perhaps in cottontail rabbits.
• 7.  The results of the study are discussed and evaluated as related to the epidemiology of the disease.

• 1.  Muscle biopsies in children with kwashiorkor reveal an increase in the number of both pale and dark nuclei of the sarcolemma, a pericapillary infiltration of the interfascicular vessels, edema, and, in more advanced cases, a fine network of connective tissue fibers in the intermysial space. This intermysial sclerosis may include some infiltrative elements (lymphocytes, more rarely histiocytes). The caliber of the muscle fibers and of the fascicles is frequently reduced. Degenerated muscle fibers occur at random. No evidence of burgeoning can be seen in any of the affected muscle fibers. The adventitial spaces of blood vessels and the small nerve fibers may show signs of edema. These findings are based upon the study of 11 cases of kwashiorkor.
• 2.  In seven cases of cachexia due to causes other than kwashiorkor, muscle tissue showed a slight increase in the number of the pale nuclei, some septal edema, slight eosinophilia of a few muscle fibers and, rarely, a few degenerated fibers.
• 3.  In both instances, the lesions are of the same type but they are uniformly more severe in the patients with kwashiorkor.
• 4.  The muscle fibers themselves would appear to be the most resistant element of the fascicle. These are involved only when the edema and the fibrous changes are advanced. This occurs only in cases of kwashiorkor presenting the full clinical picture.

The incidence of intestinal worms was determined in 664 autopsies consisting of 586 Indonesian, 69 Chinese and 9 European, all residents of Djakarta.

Hookworm was found in 89.4% among Indonesians, with an average worm load of 62.7; in 59% among Chinese with an average worm load of 39 and three times in Europeans with an average worm load of 17. The average worm load in men was higher than in women, although the incidence was about the same for both sexes. Necator americanus was most often found; Ancyclostoma duodenale, although frequently found, showed a low worm load; Ancyclostoma ceylanicum was found seven times and Ancyclostoma caninum once.

Trichuris trichiura was found in a frequency of 86.9% in Indonesians, with an average worm load of 13.3; 70% in Chinese with an average worm load of seven.

Ascaris lumbricoides was less frequent than T. trichiura. The incidence was 63.6% in Indonesians and 42% in Chinese, while the average worm load was six and four, respectively.

Oxyuris vermicularis was also found in a high frequency: 39.4% in Indonesians, 36% in Chinese and 4 cases in Europeans.

Strongyloides stercoralis and Trichostrongylus species were also found; however, no trematodes and cestodes were recovered from this series of autopsies.

Written as a guide in environmental sanitation for students in sanitary engineering, nurses, sanitarians, and physicians qualifying as health officers, this volume presents in limited detail and 21 chapters, over-all descriptions of the principles, practices and apparatuses used in environmental sanitation in the United States. Among the topics discussed are Principles of Disinfection; sanitation of food, eating places, milk and milk products; Air Pollution; Ventilation; Industrial Sanitation; Insect Control; Rodent Control; and so on. Almost half of the book is devoted to Public Water Supplies, Refuse Disposal, Rural and Urban Sewage Disposal, Stream Pollution, and Industrial Wastes. Discussions are concise and well written and unusually well illustrated. Subject matter is intelligently chosen for readers already having some background in one of the branches of preventive medicine. Each chapter has a list of supplementary reading, generally up-to-date and pertinent.

This autobiography covers in great detail nearly 80 years of the author's life. It begins with an account of his participation in the terrible Manchurian pneumonic plague epidemic of 1910. After a description of the International Plague Conference at Mukden in 1911, there is a long flashback to Wu's boyhood in Malaya, his student years at Cambridge and London, and his postgraduate work on the Continent. Following research and later private medical practice in Malaya, Dr. Wu went to China as Vice Director of the Imperial Army Medical School (Tientsin). From this post he was called to Manchuria, where he ultimately became Director of the Plague Prevention Service. In 1930 he was appointed Director of the Chinese National Quarantine Service. After the Japanese occupied Shanghai in 1937, he returned to Malaya and re-entered private practice.

In his wide and frequent travels Dr. Wu has been a keen observer.

Dr. Elek has written an impressive and scholarly book on the biology of the staphylococcus and the peculiar host-parasite relationships which appear to surround infections produced by this microorganism. This is a book which will be warmly received by all investigators struggling with the mysteries of staphylococcal disease. For the first time, the diffuse and confused experimental literature on staphylococcal disease has been collected, organized, and critically analyzed.

The chapters on antigenic structure, virulence and disease, and resistance and immune phenomena seem particularly excellent. Many ghosts have been laid to rest in these sections, and Dr. Elek's broad scientific orientation shows in many of his comments.

In his introduction Dr. Elek modestly claims to dissociate himself from the experimental studies that he reports, but it is pleasing to find that this is not the case. The author's pithy and concise comments on experimental studies are refreshing and valuable, and help to show the reader Dr. Elek's personal orientation.