Biomedical subjects
Publications and source records attributed to P C Beaver.
A nematode measuring approximately 1.25 mm by 42 micron, excised in a granuloma from the eye of a child in East Africa, was identified as a third-stage ascaridoid larva of a type having no ventriculus or cecum and bearing conspicuous lateral alae.
A 4.5-mm filarial worm was removed from the anterior chamber of the left eye of a 56-year-old man who had lost the sight in the right eye due to trauma some years earlier. The worm was removed intact through an upper scleral incision with a corneal based flap. Within 2 months vision was normal. The worm was identified as a sexually mature male of an undescribed species of Loaina Eberhard and Orihel 1984, a genus related to Loa and Dirofilaria.
A 2-year-old boy from a rural community of Costa Rica was admitted to hospital with a rash of increasing severity over an area of the flank about 8 cm in diameter. Sections of a biopsy from the center of the affected area revealed a necrotic mature, infertile, female filaria about 120 microns in diameter in a subcutaneous artery, surrounded by a layer of dense eosinophilic granulomatous reaction which at one point, along with the worm, extended into the dermis. The worm, readily distinguished from Dirofilaria, Onchocerca, Wuchereria and Brugia, was unidentified.
Thirty or more microfilariae 0.70-1.32 mm in length were recovered from the hemocele of an unengorged adult tick, Ixodes dammini, that was collected from vegetation on Shelter Island, New York. Among approximately 500 I. dammini collected from the same area only 1 other was similarly infected. Outstanding features, in addition to size, were absence of a cephalic space and the presence of nuclei in 2 or 3 irregular rows extending to the end of a bluntly rounded tail. The microfilariae apparently were ingested in a blood meal that was taken when the ticks were larvae or nymphs, and had persisted alive without development.
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An immature female acanthocephalan in a tumor on the serosa over the ileum of a 16-year-old boy in Kagoshima, Japan, was identified as probably a species of Bolbosoma. This is the second such case to be reported.
A cerebral cyst 5 cm in diameter and 60 ml in volume was found to be as large as a racemose cysticercus. Because this cyst bore necrotic remnants of a scolex and its hooks, it was presumed to be a cysticercus of Taenia solium. This case demonstrates that in contrast with the unusual presentation of cerebral cysticercosis, cysts of the Taenia solium type can be very large, and when such cyst is encountered, a special search should be made for evidence of a scolex.
A case of invasion of the brain of a 48-year-old man, a native of Louisiana, by a larval tapeworm is described. Inasmuch as there were no scolices or rostellar hooks present the parasite was identified as a racemose cysticercus which could be either a sterile coenurus of Taenia multiceps (= Multiceps multiceps), Taenia serialis (= Multiceps serialis), or an aberrant cysticercus of Taenia solium or of a different species of Taenia. Most of the parasite was removed surgically with a preoperative diagnosis of brain tumor. After operation the patient improved, and 32 months after onset of his illness he was working and showed no evidence of a recurrence.
Large tumors removed from the lower abdomen and pleural cavity of a 24-year-old male Amerindian in Paraguay consisted mainly of multitudes of minute, proliferating, acephalic cestode larvae embedded in fibrous tissue. The parasite resembled Sparganum proliferum Stiles 1908 but was markedly less differentiated. From a review of the literature and examination of available reference material, it is concluded that in addition to the present one there are eight well documented cases of proliferating acephalic larval cestode infection in man: five in Japan and one in Florida (USA) that were S. proliferum, one in Pennsylvania (USA) that was an undifferentiated cysticercus or cysticercoid, and one in Taiwan that probably was an undifferentiated tetrathyridium. In four other cases the parasites are reclassified as being of doubtful nature in three and a racemose cysticercus in one. Review of the known species of proliferating cestode larvae naturally occurring in animals failed to identify possible sources of the acephalic forms observed in man.
Sporocysts obtained in Singapore in the feces of the boid snake, Python reticulatus, were given by mouth to laboratory rats, mice, and a monkey (Macaca mulatta). Infections developed in rats only. Schizonts were observed in vascular endothelium of various tissues of rats examined at 7 to 15 days of infection; and in each of 20 rats examined at 1 mo to 2 yr, cysts of three species of Sarcocystis were observed. Based on observations made by light and electron microscopy, one species was identified as S. singaporensis and redescribed; two species, S. villivillosi and S. zamani, were described as new. The cyst wall of S. singaporensis is thick with tall, stalked, digitiform villi. That of S. villivillosi is moderately thin and bears short, stout villi that are covered with microvilli; and that of S. zamani is thin and bears delicate, branched villi. The cyst of S. zamani is macroscopic with rounded ends; it induces multiplication of host-cell nuclei and causes resorption of the myofibrils. Cysts of the other species are microscopic with fusiform shape that changes markedly with contraction of the host cell. Refrigerated sporocysts of S. singaporensis, S. zamani, and S. villivillosi remained viable for at least 24, 14, and 6 mo, respectively. Sarcocystis singaporensis and S. zamani apparently have been reported previously from several species of Malaysian wild rodents; S. villivillosi represents a unique type in rodents.
A 21-mm filarial worm appeared suddenly in the anterior chamber of the right eye of a 32-year-old man in western Oregon. By a simultaneous irrigation-aspiration procedure, it was removed alive and only slightly damaged and was identified as a female Dipetalonema in the fourth stage of development. It was the third such case to be reported from western Oregon. In this and one other case the worms were morphologically similar to adult worms identified as Dipetalonema arbuta Highby 1943 from the body cavity of the porcupine (Erethizon dorsatum) and a similar species, Dipetalonema sprenti Anderson 1953, from the body cavity of the beaver (Castor canadensis).
Dirofilaria immitis infection in dogs is an increasing problem throughout much of the United States and is no longer limited to the South. Vector mosquitos are present and transmission may occur during the summer months throughout the southern, eastern, and midwestern states. In addition to pulmonary nodules, D immitis and related species cause symptomatic subcutaneous nodules. Physicians should be alert to this differential diagnostic possibility.
A nematode in a subcutaneous nodule excised from the chest of a man in central California is described and identified as a third-stage larval dioctophymatid, probably Dioctophyma renale, though a Eustrongylides species could not be excluded. In all well-documented previously reported cases of D. renale infection in man, none of which was from North America, adult worms were discovered in the kidney at autopsy (5 cases), or were observed migrating or being expelled through the urethra (6 cases), discharged through the skin over an abscessed kidney (1 case), or detected by finding eggs in the urine (1 case).
A nematode within a subcutaneous nodule excised from an elderly Okinawan man has been tentatively identified in sections as an immature Dirofilaria repens--the first to be reported from Japan.
Three human infections with an animal filarial parasite of a Brugia species have been identification in residents of New England over the past 2 years. All patients were asymptomatic except for local, superficial lymphadenopathy. The diagnosis was established pathologically by the finding of immature brugia worms in the biopsied lymph nodes. Peripheral blood eosinophilia was lacking; in one patient, no lymphocyte blastogenesis to filarial antigens and no antifilarial antibodies were detectable. These cases document a wider geographic range in the Northeast for this zoonosis, which had been previously recognized in two residents of the Middle-Atlantic states. The clinical and pathologic features resulting from the worm's intralymphatic localization and the structure of the brugia worm distinguish this entity from other zoonotic filarial infections.
Sarcocystis was identified in biopsy specimens of skeletal muscle from two adults in Singapore and one in Bombay, and in muscle obtained at autopsy from an adult in Uganda, and in the heart of a child in Costa Rica. Review of case reports revealed that in seven reported cases, including three reported by Lindemann, non-parasite objects were misinterpreted as sarcocysts; in four instances organisms of undetermined classification were described, and in 35 cases true sarcocysts were observed. Among the sarcocysts seen in the 40 cases (35 old, 5 new), seven morphological types were recognized, each representing one to several different species, all of which are zoonotic and none of which can be designated Sarcocystis lindemanni. Among the four types of sarcocysts found in skeletal muscle, three closely resembled a corresponding species found commonly in monkeys: one from a man in Uganda corresponding to a species in Ceropithicus talapoin, forms from India resembling one or two species in Macaca mulatta, and forms from Southeast Asia resembling a species in Macaca fascicularis. Among three types of sarcocysts found in the human heart, one resembled a species commonly seen in the heart of cattle. Of the 40 Sarcocystis infections in man, 13 probably were acquired in Southeast Asia, 8 in India, 5 in Central or South America, 4 each in Africa and Europe, 3 in USA, 1 IN China and 2 in unknown localities. Associated conditions include muscle soreness or weakness in 7 cases, subcutaneous swellings in 5, eosinophilia in 2, and periarteritis or polyarteritis nodosa in 2 cases. However, evidence of pathogenicity of the mature sarcocyst is inconclusive.
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Larval nematodes identified as Eustrongylides wenrichi Canavan 1929, from cysts in the tissues of Amphiuma means tridactylum Cuvier in Louisana were redescribed. The extent of differentiation of the sex organs was found to be greater than that of 3rd-stage Dioctophyma renale, or of the infective stage of Trichinella spiralis, and comparable with the late 4th-stage larva of secernentean (phasmid) nematodes.