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Effect of organochlorine (DDT) exposure on experimental giardiasis
Fetouh A Deyab1, Kholoud A El-Nouby, Zeinab S Shoheib
1Department of Parasitology, Faculty of Medicine, Tanta University, Tanta, Egypt.
Abstract:
This work studied the effect of sub-chronic DDT exposure on the course of experimental giardiasis and efficacy of its treatment. A total of 160 mice were divided into six groups: G1: 30 mice received DDT and infected with Giardia lamblia. G2: 30 mice received DDT, infected and treated with tinidazole (TNZ). G3: 30 mice infected with Giardia. G4: 30 mice infected and treated with TNZ. G5: 30 mice received DDT only. G6: 10 mice served as normal control. Mice were sacrificed at 7, 14, 21 & 28 days P.I. All groups were subjected to cyst count/2 hours collected stool, trophozoite count in intestine, histopathological examination of small intestinal section and avidin biotin peroxidase technique for local IgA staining. Also, IFN-gamma was measured in sera. DDT caused early shedding of many cysts and increase in trophozoite counts for a long time, decreased intra epithelial lymphocytes, low levels of IgA & IFN-gamma and severe histopathological changes in intestinal sections in G1 as compared to G3. Also, DDT reduced the efficacy of TNZ treatment in G2 as compared to G4. The results strongly support the immunomodulating effect of DDT on experimental giardiasis that might be responsible for persistence of infection, resistance to treatment and re-infection in DDT exposed persons.
Insights
Sub-chronic exposure to DDT (dichlorodiphenyltrichloroethane) exacerbates giardiasis in mice, increasing parasite load and reducing treatment efficacy. This suggests DDT
Area of Science:
- Environmental toxicology
- Immunology
- Infectious diseases
Background:
- Giardiasis remains a significant global health concern.
- DDT (dichlorodiphenyltrichloroethane) is a persistent environmental pollutant with known immunomodulatory effects.
- The impact of DDT exposure on parasitic infections like giardiasis requires further investigation.
Purpose of the Study:
- To investigate the effect of sub-chronic DDT exposure on experimental giardiasis.
- To evaluate the efficacy of tinidazole treatment in the presence of DDT exposure.
- To elucidate the immunomodulatory mechanisms underlying DDT's influence on giardiasis.
Main Methods:
- A mouse model of giardiasis was established with varying DDT exposure and tinidazole treatment regimens.
- Parasite burden was assessed through cyst counts in stool and trophozoite counts in the intestine.
- Immune responses were evaluated via histopathological examination, IgA staining, and IFN-gamma measurements.
Main Results:
- DDT exposure led to increased cyst shedding and prolonged trophozoite presence in infected mice.
- DDT significantly reduced intestinal IgA levels, IFN-gamma production, and intraepithelial lymphocytes.
- Tinidazole treatment efficacy was diminished in mice exposed to DDT compared to unexposed controls.
Conclusions:
- Sub-chronic DDT exposure worsens experimental giardiasis by suppressing key immune responses.
- DDT exposure compromises the effectiveness of standard giardiasis treatment.
- These findings highlight the potential for environmental pollutants like DDT to increase susceptibility to parasitic infections and treatment failure in exposed populations.
