Cornea as a tissue reservoir of Trypanosoma cruzi

Abstract

Trypanosoma cruzi causal agent of Chagas' disease is a paninfective parasite of mammals transmitted through skin fecal contamination by Triatominae vectors. Studies of alternative routes for infection are scarce; therefore, eye infection should be important, because of the eye's high blood irrigation and brain proximity, as port of entry of the parasite. Trypanosoma cruzi parasites and/or their genetic material in ocular and adjacent muscle tissues were studied in batches of six NMRI mice (15 g) and Trichomys apereoides, an ancient caviomorph (250 g) inoculated with T. cruzi metacyclics from Brazilian (2) and Venezuelan (3) isolates genetically typified as T. cruzi I and II. Two animals/batch in the acute or chronic phase were killed and necropsies of cardiac and skeletal muscles, eyeball, and surrounding ocular muscle were processed for hematoxylin-eosine staining. Tissue parasitism was determined. DNA of the digested sections of the eyeball (5-10 mum) was extracted for T. cruzi k-DNA amplification by PCR, with S35 and S36 primers. The PCR products were analyzed. The average of maximum values of parasitemia of all infected animals was of 10(5) trypomastigotes/ml blood. Skeletal muscle and heart were colonized in patent infection for all isolates. Amastigote nests were found in corneal tissue of 2/3 of the used isolates and adjacent ocular muscle and connective tissue were parasitized. Trypanosoma cruzi k-DNA (330-bp band) was observed in ocular tissue of 4/6 of the isolates studied in both animal models. Investigations concerning infection of the eye globe tissues by T. cruzi are extremely scarce. The presence of stages of T. cruzi and/or its genetic products in ocular tissues indicate a broad colonization from a systemic infection. The results show the ocular environment as a possible appropriate microniche for T. cruzi and emphasize the risk of transmitting T. cruzi by ocular fluids and by parasitized cornea through transplants.

Chagas’ Disease: An Emergent Urban Zoonosis. The Caracas Valley (Venezuela) as an Epidemiological Model

“…Using a mouse model, the possibility of the transfer of T. cruzi was determined in organs often used during these procedures. Isolates from D. marsupialis and R. rattus captured in Caracas were inoculated in adipose, bone-cartilage, and eye tissue, observing the intracellular presence of the parasite in all cases ( 39 – 41 ) (Figures 5 – 7 ). This constitutes an alternative transmission pathway, whereby natural T. cruzi intracellular multiplication could be enhanced in immunosuppressed hosts.…”

Eye Banking and Corneal Transplantation Communicable Adverse Incidents

“…The UK Blood Transfusion and Tissue Transplantation Services, however, suggested that as there is no risk of transmitting T. cruzi because corneas are avascular. 117 Herrera et al 118 indicated that there few investigations of infection of the eye globe tissues by T. cruzi; however, their animal studies found T. cruzi in the ocular environment, which suggested the possible risk of transmission. The Canadian Blood Services has instituted a common policy to test for Chagas in blood donors in Canada and expects to implement similar policies for corneal tissue.…”

Noninvasive Biological Samples to Detect and Diagnose Infections due to Trypanosomatidae Parasites: A Systematic Review and Meta-Analysis

“…Recently, the first case of Trypanosoma cruzi-associated retinitis was diagnosed [283]. The presence of T. cruzi amastigotes in the conjunctiva, corneal stroma, the adjacent ocular muscle, and the interstitial macrophages of Thrichomys apereoides (Rodentia, Echimyidae) experimentally infected with T. cruzi has been documented [284].…”