Studies on human schistosomiasis: chemotherapy, immunity and morbidity

Butterworth, Anthony E.

doi:10.1051/parasite/1990651053

Cited by 9 publications

(4 citation statements)

References 6 publications

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“…Before female worms develop their full egg-laying capacity, sporadic deposition of eggs may take place with a proportion of these being voided into the bowel lumen and ejected in faeces whilst the remainder become trapped within the host's tissues [16] . Interacting with this are also the beginnings of the child's innate and adaptive immune responses to excretory-secretory products of the worms themselves, as well as these responses being primed or modulated by maternally induced effects, for example, during pregnancy and(or) breastfeeding [17] , [18] , [19] , [20] . It is also of particular note that the child's immune system is in a maturing flux of recognition between self- and non-self epitopes [21] and the efficacy of PZQ, which is poor against immature worms of S. mansoni [22] , is only starting to be explored in this ageclass [11] .…”

Section: Introductionmentioning

confidence: 99%

Schistosoma mansoni Infections in Young Children: When Are Schistosome Antigens in Urine, Eggs in Stool and Antibodies to Eggs First Detectable?

et al. 2011

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BackgroundIn Uganda, control of intestinal schistosomiasis with preventive chemotherapy is typically focused towards treatment of school-aged children; the needs of younger children are presently being investigated as in lakeshore communities very young children can be infected. In the context of future epidemiological monitoring, we sought to compare the detection thresholds of available diagnostic tools for Schistosoma mansoni and estimate a likely age of first infection for these children.Methods and FindingsA total of 242 infants and preschool children (134 boys and 108 girls, mean age 2.9 years, minimum 5 months and maximum 5 years) were examined from Bugoigo, a well-known disease endemic village on Lake Albert. Schistosome antigens in urine, eggs in stool and host antibodies to eggs were inspected to reveal a general prevalence of 47.5% (CI95 41.1–54.0%), as ascertained by a positive criterion from at least one diagnostic method. Although children as young as 6 months old could be found infected, the average age of infected children was between 3¼–3¾ years, when diagnostic techniques became broadly congruent.ConclusionWhilst different assays have particular (dis)advantages, direct detection of eggs in stool was least sensitive having a temporal lag behind antigen and antibody methods. Setting precisely a general age of first infection is problematic but if present Ugandan policies continue, a large proportion of infected children could wait up to 3–4 years before receiving first medication. To better tailor treatment needs for this younger ageclass, we suggest that the circulating cathodic antigen urine dipstick method to be used as an epidemiological indicator.

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Section: Introductionmentioning

confidence: 99%

Schistosoma mansoni Infections in Young Children: When Are Schistosome Antigens in Urine, Eggs in Stool and Antibodies to Eggs First Detectable?

et al. 2011

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“…The use of school children to monitor control has been rationalized because this age group has so frequently been associated with the highest age-specific prevalence and GMECs. 20 In Kafr El Sheikh, the results show a large proportion of the infection and intensity of infection present in the adult ages.…”

Section: Discussionmentioning

confidence: 92%

The epidemiology of schistosomiasis in Egypt: patterns of Schistosoma mansoni infection and morbidity in Kafer El-Sheikh.

Barakat¹,

Farghaly²,

Masry³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

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Abstract. This is a descriptive report of the Epidemiology 1, 2, 3 project in Egypt that made use of large probability sampling methods. These results focus on Schistosoma mansoni infection in the northern Nile Delta governorate of Kafr El Sheikh. A probability sample of 18,777 persons, representing the rural population of the entire governorate, was drawn. The sample was designed not to exclude villages based on location or presence of health care facilities and to include representation of the smaller ezbas or hamlets. The objective was to obtain detailed estimates on ageand sex-specific patterns of S. mansoni infection, and to provide a baseline for prospective studies. Stool specimens were examined by the Kato method. The estimated mean Ϯ SE prevalence of S. mansoni infection in the rural population was 39.3 Ϯ 3.3% in 44 villages and ezbas after weighing for the effects of the sample design. The estimated mean Ϯ SE geometric mean egg count per gram of stool (GMEC) was 72.9 Ϯ 7.3. Prevalence and GMEC varied considerably by village and ezba, with ezbas having a significantly higher prevalence. Villages and ezba-specific prevalence was strongly associated with GMEC (r 2 ϭ 0.61, P Ͻ 0.001). The prevalence of S. mansoni infection increased by age to 55.4 Ϯ 3.2% at age 16 without a significant change in the adult ages. There were no gender differences until age 6, after which males were consistently higher until middle age, when the differences converged. The age-and sex-specific pattern of GMEC varied widely; however, when the GMEC data were collapsed into 5-year age groups, the GMEC peaked at 81.5 Ϯ 12.1 eggs/g in the 10-14-year-old age group. These estimates provide the basis for evaluating control measures for reducing prevalence, intensity of infection, and transmission.Historically, both Schistosoma mansoni and S. haematobium were highly prevalent in Kafr El Sheikh in Egypt.

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“…In childhood viral infections, it is generally supposed that this is simply the result of immunity acquired after first contact (33). With schistosomiasis infections, it is possible that the lower intensities of infection seen in adults may result from acquisition of immunity due to exposure to chronic antigen stimulation (6). However, it has also been proposed that naturally acquired immunity to schistosomiasis and malaria may be linked to key features of the immune system that change during normal human development and aging (2,17).…”

mentioning

confidence: 99%

Development of Antibody Isotype Responses toSchistosoma mansoniin an Immunologically Naive Immigrant Population: Influence of Infection Duration, Infection Intensity, and Host Age

et al. 1999

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We have identified the influence of host and parasite factors that give rise to characteristic antibody isotype profiles with age seen in human populations living in different areas of schistosomiasis endemicity. This is important in the immunobiology of this disease. It is also of interest in the context of human responses to chronic antigen stimulation, vaccines, allergens, and other pathogens. In populations exposed to endemic schistosomiasis, factors such as intensity and duration of infection are age dependent. They therefore confound the influence of host age on antiparasite responses. Here, we resolved these confounding factors by comparing the developing antibody responses of an immunologically naive immigrant population as they acquired the infection for the first time with those of chronically infected resident inhabitants of the same region of Schistosoma mansoni endemicity in Kenya. Recent arrival in the area strongly favored immunoglobulin G3 (IgG3) responses against the parasite. The antibody isotype responses associated with human susceptibility to reinfection after chemotherapy were elevated in those suffering high intensities of infection (IgG4 responses against worm and egg antigens) or were characteristic responses of young children irrespective of the intensity or duration of infection (IgG2 responses against egg antigen). IgE responses against the adult worm, a response associated with resistance to reinfection after chemotherapy, increased with the ages of infected individuals and were also favored in those currently suffering higher intensities of infection.

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Studies on human schistosomiasis: chemotherapy, immunity and morbidity

Cited by 9 publications

References 6 publications

Schistosoma mansoni Infections in Young Children: When Are Schistosome Antigens in Urine, Eggs in Stool and Antibodies to Eggs First Detectable?

Schistosoma mansoni Infections in Young Children: When Are Schistosome Antigens in Urine, Eggs in Stool and Antibodies to Eggs First Detectable?

The epidemiology of schistosomiasis in Egypt: patterns of Schistosoma mansoni infection and morbidity in Kafer El-Sheikh.

Development of Antibody Isotype Responses toSchistosoma mansoniin an Immunologically Naive Immigrant Population: Influence of Infection Duration, Infection Intensity, and Host Age

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