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Journal ArticleDOI

Toxoplasma antibodies in inhabitants of the Niger Delta

01 Jan 1965-Transactions of The Royal Society of Tropical Medicine and Hygiene (Oxford University Press)-Vol. 59, Iss: 1, pp 83-86
TL;DR: A high incidence of toxoplasma antibodies has been found in adult Africans in the Niger Delta, similar to the incidence found in tropical areas of the New World.
Abstract: A high incidence of toxoplasma antibodies has been found in adult Africans in the Niger Delta. This is similar to the incidence found in tropical areas of the New World.
Citations
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Book ChapterDOI
TL;DR: In this paper, the authors focus on the literature appearing during 1963-66 in the context of toxoplasmosis and discuss the mechanisms of transmission, summarizing the serological work carried out in this regard.
Abstract: Publisher Summary This chapter focuses on the literature appearing during 1963–66 in the context of toxoplasmosis. The chapter outlines the advances in the electron microscopy of Toxoplasma and discusses the mechanisms of transmission, summarizing the serological work carried out in this regard. It also summarizes and comments on new epidemiological data and presents observations on the association of Toxoplasma with various disease conditions, papers concerned with anti-Toxoplasma drugs, and a few papers on physiology, tissue culture and toxin production of Toxoplasma. The usefulness of pyrimethamine and sulfa drugs in the treatment of toxoplasmosis has been generally accepted and well demonstrated. One disadvantage of pyrimethamine is teratogenesis. In addition, hematological side effects are frequently seen and must be monitored.

99 citations

Journal ArticleDOI
TL;DR: The Hadza, a small tribe living near Lake Eyasi, Tanzania, lived by hunting and gathering until 1964–1965 when most of them were persuaded to settle, with data on neighbouring peoples and other hunter-gatherers, especially the Bushmen of southern Africa.
Abstract: The Hadza, a small tribe living near Lake Eyasi, N. Tanzania, lived by hunting and gathering until 1964–1965 when most of them were persuaded to settle. The data reported here were collected in 1966 and 1967 and cover both settled Hadza and those still nomadic. In the dry season (1966) most of the malaria infections were in children and most of them were due to P. malariae. At the end of the wet season (1967) a higher proportion of adults were infected and about half the infections were with P. falciparum. All of 132 representative sera tested for malarial antibodies were positive. No systematic difference in malaria incidence was found between nomadic and settled groups. 72·2% of serological tests for Toxoplasma were positive and there was no significant difference between nomadic and settled groups. Trypanosomes were not detected in any of the blood films and serological tests revealed only one positive. Stool examinations showed Entamoeba coli to be more frequent in the settled than in the nomadic Hadza. Entamoeba histolytica cysts were seldom found (1·4–8·6%) and were least frequent in the nomads. Serological tests, however, were commonly positive, but again lowest in the nomads. Hookworm, Ascaris, Strongyloides, Enterobius, Taenia and Schistosoma mansoni were found only rarely. Trichuris was relatively frequent in the males of one nomadic group. Ova of S. haematobium were found in only 2 295 urine specimens and serological tests also indicated a low incidence of schistosomiasis. Few of the subjects had haemoglobin levels below 10 g. per 100 ml. The levels in adult males of the nomadic group were close to European norms and probably higher than in the settled Hadza. The levels of IgA, IgG and especially IgM are higher in the Hadza than in British subjects. The distributions of IgA and IgM levels show increased skewing as age increases. Ig levels did not appear to be raised in subjects with malaria parasitaemia or splenomegaly or in those serologically positive for schistosomiasis or amoebiasis. The results are compared with 3 earlier, more restricted, surveys of the Hadza, with data on neighbouring peoples and other hunter-gatherers, especially the Bushmen of southern Africa.

35 citations

Journal ArticleDOI
TL;DR: A review of 1987 patients with uveitis seen over an 11-year period in Bendel State of Nigeria has been undertaken; 56% of cases had a posterior/mid-peripheral Uveitis, 15.1% a panuveitis, 21.5% an anteriorUveitis were of presumed toxoplasmic origin, and leprosy, tuberculosis, and onchocerciasis were identified.
Abstract: A review of 1987 patients with uveitis seen over an 11-year period in Bendel State of Nigeria has been undertaken; 56% of cases had a posterior/mid-peripheral uveitis, 15.1% a panuveitis, 21.5% an anterior uveitis. Acute anterior uveitis with classical symptoms was rarely seen. Its comparative rarity is presumably due to the absence of HL-A27 in Africans and altered immunological states from malaria and parasitic infections. Identified aetiological factors in anterior uveitis were leprosy (1 patient), tuberculosis (1 patient), herpes zoster (16 patients), and onchocerciasis (3 patients). The great majority of cases of posterior uveitis were of presumed toxoplasmic origin. Further studies are needed to demonstrate its mode of transmission in a population in which toxoplasmosis is endemic. Forest onchocerciasis is not a major cause of uveitis in southern Nigeria in the same way as savanna onchocerciasis is in northern Nigeria. Syphilis seems to play no part in the causation of uveitis in southern Nigeria. Better diagnostic facilities are required to determine the role of sarcoidosis and other possible causative factors. Uveitis is a major cause of blindness in Nigeria.

27 citations

Dissertation
01 Jan 2010
TL;DR: In this article, a deux etudes de terrain were realized to preciser the circulation and the diversite of Toxoplasma gondii dans cet environnement tropical humide: (i) Gabon en milieu urbain and rural, avec differentes approches telles that the seroprevalence of the toxoplasmose humaine and animale analysee a l'aide des SIG et d'analyse multivariee, mais aussi l'etude de la diversite gen
Abstract: La toxoplasmose est une zoonose due au protozoaire Toxoplasma gondii largement reparti dans le monde. La zone tropicale humide presente des caracteristiques propices a sa circulation, pourtant elle reste peu etudiee vis-a-vis de ce parasite. Nous avons realise deux etudes de terrain afin de preciser la circulation et la diversite du toxoplasme dans cet environnement tropical humide : (i) au Gabon en milieu urbain et rural, avec differentes approches telles que la seroprevalence de la toxoplasmose humaine et animale analysee a l'aide des SIG et d'analyse multivariee, mais aussi l'etude de la diversite genetique et de la structure des populations du toxoplasme et (ii) en Guyane Francaise avec la caracterisation et la comparaison genetique des souches circulant dans le cycle « sauvage » et le cycle « domestique » du toxoplasme. Dans ces deux etudes l'analyse de la structure des populations a ete realisee a l'aide d'arbres de distance (Neighbor-joining), de l'etude des FST et du desequilibre de liaison, de modele statistique Bayesien (STRUCTURE) et de methodes multivariees (DAPC) integrant pour certaines des informations spatiales (sPCA). Au Gabon, la seroprevalence animale et humaine retrouvee est elevee en milieu urbain et rural, avec un risque tellurique preponderant en relation avec le niveau d'hygiene et les conditions climatiques. Les 69 isolats obtenus ont ete caracterises genetiquement et phenotypiquement au travers de la virulence chez la souris a l'isolement. Outre le Type III que l'on retrouve partout dans le monde, deux principaux haplogroupes ont ete caracterises et proposes comme nouveaux haplogroupes d'importance pour T. gondii en Afrique. Un lien avec les souches circulant en Amerique Centrale et du Sud a ete mis en evidence. L'analyse de la structure de la population montre une circulation accrue du parasite entre les principales villes du pays en relation avec les activites humaines. En Guyane Francaise, les 33 nouveaux isolats obtenus principalement de la faune peri domestique ont ete compares a 18 souches deja publiees provenant essentiellement de l'environnement sauvage. La population sauvage etait la plus diversifiee. En plus d'une structuration spatiale et genetique en deux populations refletant les deux populations environnementales, « anthropisee » et « sauvage », une sous structuration genetique a ete trouvee, confirmee pour certains groupes par des traits phenotypiques distincts (virulence chez la souris). Ces resultats suggerent aussi l'existence d‟interpenetration entre les cycles sauvage et domestique avec des risques potentiels pour la sante humaine.

24 citations

Journal ArticleDOI
TL;DR: Of 356 samples of human sera collected from native patients in two distinct zones of Somalia, 53% were positive (greater than or equal to 1:8) to the dye-test for Toxoplasma gondii antibodies, indicating that acute T. Gondii infection exists among the Somalian population.
Abstract: Of 356 samples of human sera collected from native patients in two distinct zones of Somalia, 53% were positive (greater than or equal to 1:8) to the dye-test for Toxoplasma gondii antibodies. A significantly lower incidence (P less than 0.01) of infection was found in patients living in the arid Mogadishu area, compared to that in patients from villages on the river borders, situated in humid soil zones. Furthermore, in 4.2% of the river area cases the titres were over 300 I.U., indicating that acute T. gondii infection exists among the Somalian population. These differences were regarded as being due to climatic and geographical conditions rather than to diet or socio-economic conditions.

21 citations

References
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Journal ArticleDOI
TL;DR: Comparison of males, 15 to 29 years of age, from the three test groups indicated a tendency for lower titers to be produced at higher altitudes, since sera from the Guatemalan and Costa Rican lowlands showed much higher prevalences of positive sera and higher titers than did the seras from the Guatemala military recruits, who came chiefly from higher elevations.
Abstract: Summary Blood sera from 100 persons from a plantation near Escuintla, Guatemala (elevation about 1,000 feet above sea level) were tested for Toxoplasma antibodies by the Sabin-Feldman dye test. Males and females, ages 16 to 70, were included. All sera from persons above 25 years of age gave positive reactions. The overall prevalence was 94.0 per cent. A group of 30 Guatemalan military recruits was likewise tested. These were males, ages 15 to 26 years, from various localities in Guatemala but chiefly from the central highlands (elevation 5,000 feet or higher). The overall prevalence of positive tests was 50.0 per cent. Similar tests were done on 156 sera collected at Turrialba, Costa Rica (1,800 feet elevation). Donors were males and females, ages 20 to 70 years. The overall prevalence of positive sera was 88.5 per cent. Comparison of males, 15 to 29 years of age, from the three test groups indicated a tendency for lower titers to be produced at higher altitudes. The possibility is discussed that transmission may be more frequent in warm climates than in cold. The present data seem to fit such an hypothesis, since sera from the Guatemalan and Costa Rican lowlands showed much higher prevalences of positive sera and higher titers than did the sera from the Guatemalan military recruits, who came chiefly from higher elevations. However, sufficient data are not yet available to test this relationship adequately.

42 citations

Journal ArticleDOI
TL;DR: According to a number of workers, proliferative forms of Toxoplasma gondii die rapidly outside the host and in the carcass of dead animals, and the pseudocyst form probably appears late in the subacute stage of the infection and is the only form which persists in chronic infections.
Abstract: THE ORGANISM Toxoplasma gondii is an obligate intracellular parasite. Until i.iow, no form has been found which is capable of livin-ig for extended periods outside the cells of its niumerous hosts. It is capable of invading and multiplying in a wide variety of cell types, such as neurons, microglia, endothelium, reticulum, parenchyma cells of the liver, epithelial cells of the lung and glanids, and cardiac and skeletal nuscle. The parasite exists in two forms. The proliferative form., seen during the acute stage of the infection, undergoes rapid intracellular mtultiplication, and the numerous loosely grouped toxoplasmas thus produced are liberated by rupture and invade new cells. This form of the parasite is motile, showing twisting movements of its attenuated end and gliding movements unaccompanied by any changes in shape or surface visible by ordinary light microscopy. It measures about 3 by 6 microns, has a centrally loca.ted nucleus, and glycogen granules of small size. The pseudocyst form probably appears late in the subacute stage of the infection and is the only form which persists in chronic infections. Pseudocysts are generally larger in size than the cells parasitized by proliferating forms. The parasites within them, which are closely packed and more lanceolate, have a subterminal nucleus and larger glycogen gralnules (1). The latter can be considered characteristic of a resting organism. The wall of the pseudocyst is considered by soine worlkers a's the remains of the host cell wall to whlich are added some products of the parasite. Others regard it as primarily of parasitic origin. Whatever its origin, the wall of the pseudocyst is argyrophilic and elastic, and at least somewhat resistant to mechanical damage. Also, the psudocyst appears to be more resistant to environmental changes than are proliferative forms (2). According to a number of workers, proliferative forms of Toxop7cw?ma die rapidly outside the host and in the carcass of dead animals. These forms are destroyed on drying, on changes in osmotic pressure, and on exposure to low heat. Pseudocysts are also unable to withstand drying and are killed by low heat. However, they may survive in dead tissues for up to 2 weeks or longer at refrigerator temperatures, possibly with less attrition than proliferative forms (3). The poinit of greatest difference is in survival during digestion. It is revealed indirectly by feeding experiments. Tissues of mice dying of acute toxoplasmosis fed to other mice produce relatively few infections (4). However, when tissues from chroniDr. Jacobs is head of the Section on Protozoal Diseases, Laboratory of Tropical Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Public Health Service. Based on a paper presented before the Conference of Public Health Veterinarians, November 16, 1956, in Atlantic City, N. I.

35 citations

Journal ArticleDOI
TL;DR: It was concluded that rodents play no part in the epidemiology of schistosomiasis, and the fact that wild rodents have been found infected in Nature with schisostomes is of academic interest only and should not be taken into account in any potential control scheme.
Abstract: After numerous postmortem examinations of wild rodents taken from several sites in the Eastern Transvaal Lowveld with different epidemiological conditions, but common high S. mansoni, S. haematobium and S. mattheei infection rates amongst the human beings and cattle, and after several laboratory investigations, it was concluded, for reasons which are discussed, that rodents play no part in the epidemiology of schistosomiasis. The fact that wild rodents have been found infected in Nature with schisostomes is of academic interest only and should not be taken into account in any potential control scheme.

33 citations

Journal ArticleDOI
TL;DR: The patient, a girl aged 5 years, presented with hydrocephalus, bilateral pes cavus, and blindness, and radiographs of the skull showed areas of cerebral calcification.
Abstract: A case of congenital toxoplasmosis has recently been seen in this hospital The patient, a girl aged 5 years, presented with hydrocephalus, bilateral pes cavus, and blindness. The eyes showed extensive retinochoroiditis thought to be characteristic of toxoplasmosis. Radiographs of the skull showed areas of cerebral calcification. Two years before the birth of the patient the mother had suffered from an illness accompanied by a rash and headache, thought to be rubella. Otherwise there was no family history suggestive of toxoplasmosis, and the mother was in good health. The clinical aspects of this case are being reported elsewhere. Although cases of toxoplasmosis are being reported from all over the world, so far only three cases have been published in England. In the case of Jacoby and Sagorin (1948) the serological confirmation of the diagnosis was obtained from Dr. Sven Gard, of Stockholm, and in the two cases of Farquhar and Turner (1949) the serology was done by Dr. Sabin, of Cincinnati. Owing to the apparent rarity of the disease few laboratories in this country deemed it worth while maintaining a strain of Toxoplasma, but as more

23 citations

Journal ArticleDOI
TL;DR: The original aims of the work to be reported here were two: to obtain representative groups of vegetarian Hindus and other populations in the same locale for an adequate comparison and to report the prevalence of Toxoplasma dye-test antibodies or skin sensitivity among population groups in different geographic areas.
Abstract: Several serologic surveys have reported the prevalence of Toxoplasma dye-test antibodies or skin sensitivity among population groups in different geographic areas. A summary and interpretation of a number of these papers are given by Jacobs (1956a), and Feldman and Miller (1956) present a review of their own findings. A discussion of survey data in relation to climate is given by Gibson and Coleman (1958). The original aims of the work to be reported here were two: First, previous studies on vegetarians had shown an apparently lower prevalence of positive reactions than might have been expected in a group of comparable age from the general population, but these vegetarian serums were of such diverse geographic origin that there was no really comparable control group (Jacobs, 1957). Since Trinidad has a sizeable population of East Indians, we hoped (in vain) that we might be able to obtain representative groups of vegetarian Hindus and other populations in the same locale for an adequate comparison.

18 citations