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Waterborne toxoplasmosis investigated and analysed under hydrogeological assessment: new data and perspectives for further research.

Vieira FP, Alves Mda G, Martins LM, Rangel AL, Dubey JP, Hill D, Bahia-Oliveira LM - Mem. Inst. Oswaldo Cruz (2015)

Bottom Line: Serologic testing of human specimens was done using conventional commercial tests and a sporozoite-specific embryogenesis-related protein (TgERP), which is able to differentiate whether infection resulted from tissue cysts or oocysts.However, seroprevalence in free-range chickens was significantly associated with vulnerability of groundwater to surface contamination (p < 0.0001; odds ratio: 4.73, 95% confidence interval: 2.18-10.2).Surprisingly, a high prevalence of antibodies against TgERP was detected in human specimens, suggesting the possibility of a continuous contamination of drinking water with T. gondii oocysts in this endemic setting.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Biologia do Reconhecer, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brasil.

ABSTRACT
We present a set of data on human and chicken Toxoplasma gondii seroprevalence that was investigated and analysed in light of groundwater vulnerability information in an area endemic for waterborne toxoplasmosis in Brazil. Hydrogeological assessment was undertaken to select sites for water collection from wells for T. gondii oocyst testing and for collecting blood from free-range chickens and humans for anti-T. gondii serologic testing. Serologic testing of human specimens was done using conventional commercial tests and a sporozoite-specific embryogenesis-related protein (TgERP), which is able to differentiate whether infection resulted from tissue cysts or oocysts. Water specimens were negative for the presence of viable T. gondii oocysts. However, seroprevalence in free-range chickens was significantly associated with vulnerability of groundwater to surface contamination (p < 0.0001; odds ratio: 4.73, 95% confidence interval: 2.18-10.2). Surprisingly, a high prevalence of antibodies against TgERP was detected in human specimens, suggesting the possibility of a continuous contamination of drinking water with T. gondii oocysts in this endemic setting. These findings and the new proposed approach to investigate and analyse endemic toxoplasmosis in light of groundwater vulnerability information associated with prevalence in humans estimated by oocyst antigens recognition have implications for the potential role of hydrogeological assessment in researching waterborne toxoplasmosis at a global scale.

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Toxoplasma gondii seroprevalence according to age, asdetermined by conventional ELISA (●) and T.gondiiembryogenesis-related protein (TgERP) ELISA (■) for 128individuals; B: degree of antigenic recognition, as assessed by TgERP ELISAaccording to the age range of the study population. Optical density (OD) valuegreater than 1,000 was established arbitrarily to regard individuals havinghigher degree of positivity against TgERP (see Subjects, Materials andMethods).
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f02: Toxoplasma gondii seroprevalence according to age, asdetermined by conventional ELISA (●) and T.gondiiembryogenesis-related protein (TgERP) ELISA (■) for 128individuals; B: degree of antigenic recognition, as assessed by TgERP ELISAaccording to the age range of the study population. Optical density (OD) valuegreater than 1,000 was established arbitrarily to regard individuals havinghigher degree of positivity against TgERP (see Subjects, Materials andMethods).

Mentions: Human seroprevalence of toxoplasmosis based on conventional and TgERPserology - Serology in humans was evaluated by both conventional ELISA andTgERP ELISA, as shown in Fig. 2 and in theTable. In humans, the prevalence of IgG antibodies,as measured by both TgERP ELISA and conventional ELISA, was higher in areas with ahigher degree of groundwater vulnerability (Table). However, no statistically significant differences in seroprevalence wereobserved when considering the degree of groundwater vulnerability. In Fig. 2A, the seroprevalence of conventional antigens and TgERPare compared as a function of the age range of the patients, independent of whether theywere from areas of moderate, high or extreme groundwater vulnerability. The prevalencecurves for conventional antigens and TgERP are parallel in the section of the curveswhere the slope is highest (from 8-29 years old); in this age range, six individualswere positive exclusively for TgERP (they were negative by conventional ELISA). Afterthe age of 20, the seroprevalence of TgERP was stable at approximately 50%. None ofthese individuals had IgM levels compatible with recently acquired toxoplasmosis, asdetected by conventional serology (data not shown). In Fig. 2B, the degree of antigenic recognition assessed by TgERP ELISA isexpressed in terms of OD values higher or lower than 1,000 as a function of the agerange of the groups, independent of whether patients were from areas of moderate, highor extreme groundwater vulnerability. Only TgERP-positive individuals (n = 63) are shownin Fig. 2B. The number of individuals presentingOD greater than 1,000 is higher for younger individuals groups and decreases with age,indicating that probably the infection is more recent in those individuals. The numbersin brackets represent the numbers of individuals in each age group in Fig. 2A, B.


Waterborne toxoplasmosis investigated and analysed under hydrogeological assessment: new data and perspectives for further research.

Vieira FP, Alves Mda G, Martins LM, Rangel AL, Dubey JP, Hill D, Bahia-Oliveira LM - Mem. Inst. Oswaldo Cruz (2015)

Toxoplasma gondii seroprevalence according to age, asdetermined by conventional ELISA (●) and T.gondiiembryogenesis-related protein (TgERP) ELISA (■) for 128individuals; B: degree of antigenic recognition, as assessed by TgERP ELISAaccording to the age range of the study population. Optical density (OD) valuegreater than 1,000 was established arbitrarily to regard individuals havinghigher degree of positivity against TgERP (see Subjects, Materials andMethods).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660623&req=5

f02: Toxoplasma gondii seroprevalence according to age, asdetermined by conventional ELISA (●) and T.gondiiembryogenesis-related protein (TgERP) ELISA (■) for 128individuals; B: degree of antigenic recognition, as assessed by TgERP ELISAaccording to the age range of the study population. Optical density (OD) valuegreater than 1,000 was established arbitrarily to regard individuals havinghigher degree of positivity against TgERP (see Subjects, Materials andMethods).
Mentions: Human seroprevalence of toxoplasmosis based on conventional and TgERPserology - Serology in humans was evaluated by both conventional ELISA andTgERP ELISA, as shown in Fig. 2 and in theTable. In humans, the prevalence of IgG antibodies,as measured by both TgERP ELISA and conventional ELISA, was higher in areas with ahigher degree of groundwater vulnerability (Table). However, no statistically significant differences in seroprevalence wereobserved when considering the degree of groundwater vulnerability. In Fig. 2A, the seroprevalence of conventional antigens and TgERPare compared as a function of the age range of the patients, independent of whether theywere from areas of moderate, high or extreme groundwater vulnerability. The prevalencecurves for conventional antigens and TgERP are parallel in the section of the curveswhere the slope is highest (from 8-29 years old); in this age range, six individualswere positive exclusively for TgERP (they were negative by conventional ELISA). Afterthe age of 20, the seroprevalence of TgERP was stable at approximately 50%. None ofthese individuals had IgM levels compatible with recently acquired toxoplasmosis, asdetected by conventional serology (data not shown). In Fig. 2B, the degree of antigenic recognition assessed by TgERP ELISA isexpressed in terms of OD values higher or lower than 1,000 as a function of the agerange of the groups, independent of whether patients were from areas of moderate, highor extreme groundwater vulnerability. Only TgERP-positive individuals (n = 63) are shownin Fig. 2B. The number of individuals presentingOD greater than 1,000 is higher for younger individuals groups and decreases with age,indicating that probably the infection is more recent in those individuals. The numbersin brackets represent the numbers of individuals in each age group in Fig. 2A, B.

Bottom Line: Serologic testing of human specimens was done using conventional commercial tests and a sporozoite-specific embryogenesis-related protein (TgERP), which is able to differentiate whether infection resulted from tissue cysts or oocysts.However, seroprevalence in free-range chickens was significantly associated with vulnerability of groundwater to surface contamination (p < 0.0001; odds ratio: 4.73, 95% confidence interval: 2.18-10.2).Surprisingly, a high prevalence of antibodies against TgERP was detected in human specimens, suggesting the possibility of a continuous contamination of drinking water with T. gondii oocysts in this endemic setting.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Biologia do Reconhecer, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, RJ, Brasil.

ABSTRACT
We present a set of data on human and chicken Toxoplasma gondii seroprevalence that was investigated and analysed in light of groundwater vulnerability information in an area endemic for waterborne toxoplasmosis in Brazil. Hydrogeological assessment was undertaken to select sites for water collection from wells for T. gondii oocyst testing and for collecting blood from free-range chickens and humans for anti-T. gondii serologic testing. Serologic testing of human specimens was done using conventional commercial tests and a sporozoite-specific embryogenesis-related protein (TgERP), which is able to differentiate whether infection resulted from tissue cysts or oocysts. Water specimens were negative for the presence of viable T. gondii oocysts. However, seroprevalence in free-range chickens was significantly associated with vulnerability of groundwater to surface contamination (p < 0.0001; odds ratio: 4.73, 95% confidence interval: 2.18-10.2). Surprisingly, a high prevalence of antibodies against TgERP was detected in human specimens, suggesting the possibility of a continuous contamination of drinking water with T. gondii oocysts in this endemic setting. These findings and the new proposed approach to investigate and analyse endemic toxoplasmosis in light of groundwater vulnerability information associated with prevalence in humans estimated by oocyst antigens recognition have implications for the potential role of hydrogeological assessment in researching waterborne toxoplasmosis at a global scale.

Show MeSH
Related in: MedlinePlus