The American Journal of Tropical Medicine and Hygiene - Volume 11, Issue 6, November 1962

Clinical and laboratory findings in 30 autochthonous cases of kala-azar from an area in the center of Upper Nile Province, Republic of Sudan, are presented. The value of culture technics and of bone marrow puncture in the diagnosis of the disease is emphasized. In general, kala-azar in this area appears to resemble visceral leishmaniasis as encountered elsewhere; however, a case fatality rate of over 20% apparently due to complications in hospitalized patients, the absence of leishmania in the peripheral blood, and the finding of patients from all age groups is contrary to the usual pattern of the disease in other countries. The significance of these findings is discussed.

Injection of heat-killed Ascaris eggs into the subcutaneous tissue, skeletal muscle and peritoneal cavity of rats and into the liver of rabbits results in an inflammatory reaction identical to that following the injection of live eggs. This suggests that the metabolic products of the live embryo play little or not role in the genesis of the inflammatory reaction.

The removal of the chitinous layer by chemical means does not alter the type or evolution of the inflammatory lesions, except for a less marked eosinophilic response.

The more intense inflammatory response in the immune animals within 24 hours after inoculation as well as the presence of fibrinoid necrosis in pseudotubercles, the faster resorption of injected eggs and the more rapid healing of the lesions in comparison with the controls, suggests an immunological process in the pathogenesis of these lesions.

The absence of histologic alterations following the injection of lipids extracted from Ascaris eggs in easily resorbable suspension and the similarity of the inflammatory process subsequent to the injection of either whole, decorticated or lipid-free eggs and of lipids in poorly resorbable form indicate that the granulomatous inflammation is chiefly an unspecific response from the tissues of the host against the foreign material injected.

In a series of 330 autopsies of Puerto Rican males over 10 years of age systematically studied for filarial worms by a clearing technique, filarial lesions were found in the scrotal organs in 23.9% of the cases. The 79 filarial cases had from one to seven worms each in the cord, epididymis or testis, and only 6.1% of 191 worms found were morphologically intact. The incidence of filarial disease and its correlation with microfilaremia is discussed in the light of these data.

Lesions of the tunica and cord occurred with progressive predominance in the older age groups in both filarial and non-filarial patients. However, the incidence of lesions of the genital organs (hydrocele, thickening of tunica vaginalis, etc.) was about twice as great in filarial as in non-filarial cases and the severity of the lesions was related to the number and location of the filarial worms, and the age of the patients. The disease pattern described here may represent a rather persistent subclinical form of Bancroftian filariasis in Puerto Rico.

A study of the microfilarial behavior and vectorparasite interactions has been made with Anopheles quadrimaculatus during the early phase of infection with the microfilariae of Brugia pahangi. Both living and sectioned mosquitoes with heavy and light infections were examined at 5, 15, 30 and 60 minutes following engorgement. The penetration of the midgut and subsequent migration within the mosquito, including invasion of the indirect flight muscles, is achieved mechanically through the use of the cephalic hook of the microfilaria. The site of penetration of the midgut is most commonly the area adjacent to the attachment of the hindgut; most of the microfilariae escape into the hemocele between 5 and 15 minutes following engorgement. They accumulate within the hemocele at the posterior tip of the abdomen and between 15 and 30 minutes proceed toward the thorax by a route just beneath the abdominal cuticle within the subcuticular fat bodies. Microfilariae first occur in the thorax by 15 minutes and maximum invasion of the indirect flight muscles is reached between 30 and 60 minutes after the blood meal. Penetration of the muscles occurs principally at their insertions on the cuticle. This pattern of behavior is followed in both heavily and lightly infected mosquitoes. Mechanical damage to the midgut epithelium results from the penetrating activity of the microfilariae. The migration to the thorax produces a marked degree of damage and necrosis within the subcuticular fat bodies; this is related to the intensity of infection. The beginning of pigmental encapsulation of microfilariae in the hemocele or fat bodies occurs as rapidly as 15 minutes after engorgement. This phenomenon appears to be a true host reaction to the parasite.

A case of ocular angiostrongyliasis in a Thai male aged 34 years, in Bangkok, is reported. It is the third case of Angiostrongylus infection in man, the first in Thailand, and the first to be reported involving the eye.

A living nymph of Linguatula serrata, a pentastomid, was removed from the anterior chamber of the eye of an 8-year-old colored girl from central Mississippi. The patient received injury to the eye resulting in dislocation of the lens and secondary glaucoma for which a cyclodialysis was performed. After about 3 weeks the glaucoma recurred and at this time the parasite was first seen in motion within a fine translucent capsule in the pupillary area. The parasite was removed in its capsule and the patient recovered uneventfully. The source of infection could not be established. Photographs were made of the living nymph which measured about 4.6 mm. by 1.5 mm. These confirm various anatomical structures previously described by others. The case is presented because of its rarity and general interest.

The parasitologic results of stool examinations from 907 and anal swabs from 1324 Indians on five reservations in the United States have been tabulated. Sixty-nine percent of the Indians examined were positive for one or more organisms. The over-all percentage of Entamoeba histolytica was found to be 14.9% and the amebic prevalence rate (APR), used as an index of protozoan infection, was 53.5%. With the exception of Enterobius vermicularis, no helminths other than Hymenolepis nana and one infection of Trichuris were found. The prevalence rate for E. vermicularis was 16.0% and for H. nana, 3.7%.

The parasite rates are high even in the youngest group (0 to 5) and continue at a fairly high level throughout the various ages with a peak in the 6 to 9 year group. An age-sex distribution reveals that the peaks of E. histolytica and E. vermicularis rates occur in the 6 to 9 year group in both sexes; however, while the APR peak for males also occurs in this group, in females it is in the 20 to 44 age group. In general, the rates in females are higher than in the males.

No clear-cut correlation with environmental factors could be found, although crowding (2 or more persons per room) was associated with higher rates. Also, the rates may have been affected by poor toilet facilities, poor water supplies, and the inaccessibility of water within the home.

An indication of possible racial susceptibility was found in that the protozoa rates tended to increase directly with the proportion of Indian blood. E. vermicularis rates were higher in the part-Indian groups, however.

On four of the five reservations surveyed, the prevalence of intestinal protozoa is two to four times greater in the Indians than reported in surveys of non-Indian populations in the United States. The fifth, Lac Courte Oreilles, had a very low rate, the reasons for which are not clearly understood.

The incidence of intestinal protozoa and helminths in a total of 1089 persons (mixed ages, backgrounds, localities, ethnic groups, etc.) in the Colony of British North Borneo was determined by examination of a single stool specimen by the direct smear (MIF) and the MIFC concentration techniques. Overall prevalences for the protozoa were much less than expected in an area where epidemiological conditions appeared to favor parasitization. Entamoeba histolytica occurred in only 0 to 3% of seven groups of people, indicating that amebiasis may not necessarily be a disease of great concern in all populations of the tropics. Other protozoa also occurred in limited numbers, i.e., Entamoeba hartmanni, 0 to 12%; Entamoeba coli, 4 to 30%; Endolimax nana, 2 to 12%; and Iodamoeba bütschlii, 0 to 2%. Giardia and Chilomastix occurred in 3 to 16 and 0 to 1% respectively of the people examined.

Hookworm (27 to 72%), Ascaris (13 to 74%), and Trichuris (41 to 89%) infections were commensurate with epidemiological conditions in the area, but Trichostrongylus was not recorded. Hymenolepis and Taenia were rare and Clonorchis occurred only in Chinese who probably acquired infections outside Borneo. Several persons passed eggs of heterophyid and unidentified trematodes.

In a survey of the parasitic infections in the poor and the more well-to-do negroid indigenous populations, and in the immigrant negroid and white populations of Curaçao, it was found that the highest rate of infection was in the immigrant negroes, the lowest in the immigrant whites. The immigrant whites had the highest prevalence rates of pathogenic intestinal bacilli, the immigrant Negroes the highest rates of worm infection. E. histolytica was most prevalent in the indigenous groups.

In the indigenous groups anemia was more prevalent among the poor. This was thought to be due to a deficient intake of iron, which has been demonstrated by food surveys in this region, and also to a higher prevalence of low gastric acid values.

A lowering action on the hemoglobin due to parasitic infection could be found only in the females of the poorer group. As in this group no differences in the stomach acid values could be found, nor differences in ages between the infected and non-infected persons, it was supposed that the anemia of the infected group was due to the extra burden of normally harmless intestinal parasites on ill-fed people.

Autopsy and clinical findings on six cases of pulmonary aspergillosis associated with hepatic amebic abscess are reviewed. In no case was aspergillosis suspected on clinical grounds. The possible mechanisms involved in this uncommon association are discussed. A brief review of the literature concerning pulmonary aspergillosis is given.

Eight potential areas of histoplasmosis endemicity in the Republic of Panama and the Canal Zone were located by isolation of Histoplasma capsulatum from soil or bat guano. Endemic sites include a flower garden, a bat cave, a tree frequented by bats and a previously unrecognized ecologic environment associated with tree buttresses in tropical forests.

The microorganism was shown to persist in the soil at known positive sites by repeated recovery at the beginning, end and during both the rainy and dry seasons.

H. capsulatum was recovered from livers and spleens of fructiverous bats 11 weeks after intraperitoneal inoculation with the mycelial phase of the microorganism.

Microsporum gypseum was recovered from 31% of the specimens processed using a human hair bait culture technique.

The endemicity of two areas in the Canal Zone, where clinical cases of histoplasmosis had occurred, was established by recovery of Histoplasma capsulatum from animals with naturally acquired histoplasmosis. H. capsulatum was isolated from twelve spiny rats (Proechimys semispinosus), seven common opossums (Didelphis marsupialis) and four “four-eyed” opossums (Philander o. fuscogriseus).

The presence or absence of histoplasmin hypersensitivity and complement-fixing antibodies could not be correlated with culture results in the 90 spiny rats studied. The ear of the spiny rat was found to be a good site for determining the histoplasmin sensitivity of these animals.

A probing ecologic study was conducted in south-central Florida during May, June and July, 1960, and August, 1961, to determine the nature and distribution of arthropod-borne viruses in this area. Collections for virus and/or antibody examination included 1380 specimens composed of arthropod pools, birds, small mammals, reptiles and sentinels (mice and chicks).

EEE virus was isolated from two pools of Culex mosquitoes (mixed species) and from a Common Grackle. WEE was recovered from a pool of Aedes taeniorhynchus, and the Highlands J strain of WEE from the blood of two Blue Jays and the brain of a sentinel mouse.

Antibody rates in birds which were high for EEE (21%) and WEE (23%) in the 1960 collection and indicated recent infections, were markedly lower (2.7% and 3.4%, respectively) in 1961. Bird plasma reactors to SLE were similar (8% in 1960, 5% in 1961), except positives were found with blood from juvenile birds in 1961 but not in 1960, indicating probably recent activity of SLE or a related group B arthropodborne virus in the 1961 bird population sampled. HI antibody rates in wild-caught rodents in 1960 were: WEE, 10%; SLE, 30%; EEE, 0%.

There were marked differences in two WEE strain antigens when used to measure antibody levels in birds. Forty-three or 10% of the samples were positive using the RI strain and 95 or 23% using the HJ strain of WEE. Moreover, a variance in the level of antibody was noted in bird plasmas examined by the HI and neutralization tests. These differences were attributed to the asynchronous development and/or disappearance of these antibody types.

The 17D strain yellow fever (YF) virus multiplied in primary trypsinized kidney cell cultures from chicken, guinea pig, hamster, hog and Japanese monkey (Macaca fuscata), but apparently not in rabbit kidney cell cultures. The longest periods in which active virus was detected in the infected culture fluid and the highest viral titers (mouse-intracerebral LD50/0.02 ml) obtained in the present study were: chicken kidney, 30 days, 103.5; guinea pig kidney, 14 days, 103.25; hamster kidney, 36 days, 104.25; hog kidney, 50 days, 103.75; and monkey kidney, 43 days, 103.5.

The 17D virus was transmitted through a number of hamster kidney cell ultures. Infectivity for mice was shown with the 44th passage's culture fluid representing 10-68 dilution of the starting inoculum. The cultivated virus retained its mouse-infectivity throughout the subcultures.

The infected hamster and monkey kidney cells exhibited degeneration visible under an ordinary light microscope. The cellular degeneration was prevented by antiserum from rabbits immunized with the original 17D virus. The in vitro neutralization paralleled the conventional mouse brain tests. A tendency was shown that ID50 values of 17D virus for hamster kidney cell cultures were higher than LD50's for 3-week-old mice, and that the cellular degeneration in cultures appeared earlier than the death of mice. Similar results were obtained in experiments using the mouse brain or cell culture passaged virus or the commercial chick embryo vaccine virus.

Evidence has been presented to support the hypothesis of Meers that the presence of complement-fixing (CF) antibodies to viruses serologically related to yellow fever interfered in a small proportion of persons with antibody response after vaccination with 17D mouse brain yellow fever virus by skin scarification: 96.2% conversion among 157 persons without CF antibodies for related viruses as compared with 84.5% conversion among 129 persons with such antibodies. The data were shown to be statistically significant. No correlation was found between prior infection with Ilesha virus, an arthropodborne virus serologically unrelated to yellow fever, and antibody conversion after 17D yellow fever vaccination.

It was found that some of the persons who failed to convert, on the basis of tests on blood obtained 30 days after vaccination, had demonstrable yellow fever antibody in later blood specimens.

A detailed chronology of the events associated with the 1943–1944 epizootic in Trinidad due to the virus of Venezuelan equine encephalomyelitis is presented. Findings have been assessed from the standpoint of information available to the original investigators, as well as from the vantage point of 1961.

All known data pertaining to possible human infections, including two reported fatal cases, are reviewed and it is concluded that neither fatal case has been shown conclusively to have been due to VEE infection.

Although the Trinidad strain of VEE has continued to produce brief febrile illnesses in laboratory personnel wherever it has been studied, during the epizootic recognized clinical illness in man in nature was most uncommon, if in fact it occurred at all.

No disease syndrome, either in man or in equines, due to naturally acquired VEE has been recognized in Trinidad since 1944.

A total of 687 sera from adults and children in three areas of Trinidad were tested for the presence of neutralizing antibodies against VEE virus. In southwestern Trinidad, the area involved in the 1943–1944 epizootic, antibodies were found only in sera from individuals living in 1944. In the Port of Spain area, evidence of post-1944 experience with the virus was very slight. By contrast, in the non-epizootic area of central Trinidad, an appreciable incidence of serological positivity was found in all age groups, including children born after 1944, some even born as late as 1949. Possible explanations for these last findings are discussed. Of these, the most tenable postulates the existence in this area of a well-established focus of VEE virus, or a closely related strain, which produces essentially symptomless infection in man. Possible origins of this focus are considered.

Isolation of numerous strains of VEE virus from mosquitoes, sentinel mice and field rodents in Trinidad in 1959, 1960 and 1961 is reported. These constitute the first recoveries of this agent in Trinidad since the original isolations in 1943.

The rates and sites of accumulation of equine encephalomyelitis virus in tissues of young adult mice following infection by a peripheral route were studied. Virus was detected in circulating blood and in thymus 2 hours after inoculation with a small dose of virus (about 400 LD50). Virus could be recovered from all tissues examined at 6 hours, at which time definite increase in virus content could be demonstrated. The primary site of multiplication of virus could not be determined with certainty because of the rapid development of viremia. Maximum infectivity was attained in non-nervous tissues in 24 to 48 hours after inoculation. Concentration of infective virus decreased most rapidly after 4 days in blood and liver.

Virus accumulated more slowly in brain, but eventually reached the highest content found in any organ, then persisted at high titer throughout the course of the illness.

VEE virus was recovered from urine as well as from feces collected from mice 3 days after infection, prior to appearance of clinical signs of illness.

Eggs of Oncomelania formosana were isolated from petri dishes used as laying chambers by daily inspection and were placed in various dilutions of experimental molluscicide solutions (EMS) or controls of spring water. The sulfonated hydrocarbon Tide in 1:1,000 dilution continuously applied, destroyed all eggs while 1:10,000 caused 90% mortality. Copper sulfate 1:100,000 prevented most eggs from hatching while sodium pentachlorophenate 1:2,000,000 continously applied prevented 90% hatching.

All molluscicides were more effective when applied for seven days or continuously than when applied for a day only.

Eggs left undisturbed and exposed to the molluscicides were found much more resistant to sulfonated hydrocarbon and sodium pentachlorophenate but not to copper sulfate. Increased concentration of the molluscicides erased this differential thought to be caused by the relative sizes of the molecules.