Acute trichinellosis increases susceptibility to Giardia lamblia infection in the mouse model

• Published in: Parasitology Vol. 133; no. 2; pp. 139 - 149
• Main Authors: von ALLMEN, N., CHRISTEN, S., FORSTER, U., GOTTSTEIN, B., WELLE, M., MÜLLER, N.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.08.2006
• Subjects: Animals; Biological and medical sciences; Cells; Disease Models, Animal; Disease Susceptibility; Female; Fundamental and applied biological sciences. Psychology; General aspects; General aspects and techniques. Study of several systematic groups. Models; Giardia lamblia; Giardia lamblia - growth & development; giardiasis; Giardiasis - complications; Giardiasis - epidemiology; Giardiasis - immunology; Humans; Immunization; Immunoglobulin E - immunology; Immunohistochemistry; Infiltration; Interleukin-6 - immunology; intestinal immune response; intestinal inflammation; Invertebrates; Investigations; Mast Cells - immunology; Mice; Mice, Inbred C57BL; Musicians & conductors; Nematoda; Nematodes; Nitric oxide; Parasites; Parasitology; Rodents; Specific Pathogen-Free Organisms; Studies; Technical support; Trichinella spiralis; Trichinella spiralis - physiology; trichinellosis; Trichinellosis - complications; Trichinellosis - epidemiology; Trichinellosis - immunology; Giardia lamblia; Trichinella spiralis; trichinellosis; intestinal inflammation; giardiasis; intestinal immune response; Protozoal disease; Diplomonadida; Nematoda; Protozoa; Immune response; Acute; Rodentia; Parasite; Inflammation; Parasitosis; Defense; Infection; Vertebrata; Mammalia; Sensitivity resistance; Mouse; Giardiasis; Helmintha; Nemathelminthia; Models; Invertebrata
• ISSN: 0031-1820; 1469-8161
• DOI: 10.1017/S0031182006000230

The intestinal protozoan parasite Giardia lamblia causes diarrhoea in humans and animals. In the present study, we used the C57BL/6 inbred mouse model to assess the impact of a nematode (Trichinella spiralis) infection on the course of a G. lamblia (clone GS/M-83-H7) infection. Acute trichinellosis coincided with transient intestinal inflammation and generated an intestinal environment that strongly promoted growth of G. lamblia trophozoites although the local anti-Giardia immunoglobulin (Ig) A production was not affected. This increased G. lamblia infection intensity correlated with intestinal mast cell infiltration, mast cell degranulation, and total IgE production. Furthermore, a G. lamblia single-infection investigated in parallel also resulted in intestinal mast cell accumulation but severe infiltration was triggered in the absence of IgE. Recently, intestinal mast cells emerging during a G. lamblia infection were reported to be involved in those immunological mechanisms that control intestinal proliferation of the parasite in mice. This anti-giardial activity was assumed to be related to the capacity of mast cells to produce IL-6. However, this previous assumption was questioned by our present immunohistological findings indicating that murine intestinal mast cells, activated during a G. lamblia infection were IL-6-negative. In the present co-infection experiments, mast cells induced during acute trichinellosis were not able to control a concurrent G. lamblia infection. This observation makes it feasible that the T. spiralis infection created an immunological and physiological environment that superimposed the anti-giardial effect of mast cells and thus favoured intestinal growth of G. lamblia trophozoites in double-infected mice. Furthermore, our findings raise the possibility that intestinal inflammation e.g. as a consequence of a ‘pre-existing’ nematode infection is a factor which contributes to increased susceptibility of a host to a G. lamblia infection. The phenomenon of a ‘pre-existing’ nematode infection prior to a G. lamblia infection is a frequent constellation in endemic areas of giardiasis and may therefore have a direct impact on the epidemiological situation of the disease.