La Toxoplasmosis observada como un problema no resuelto / Toxoplasmosis: an unsolved problem

Un tercio de la población mundial poseen anticuerpos contra Toxoplasma gondii. El hombre se infecta a través de los esporozoitos provenientes de las heces de los gatos que contaminan la tierra, frutas, verduras y al agua; de los bradizoitos presentes en carnes que lo infectan cuando la consume poco cocinada o por su manipulación y por trofozoitos circulantes durante la fase hematógena en el hombre, infecta al feto a través de la placenta y a individuos seronegativos por órganos sólidos trasplantados o transfundidos con elementos formes de la sangre; son los llamados grupos de riesgos los más vulnerables a desarrollar formas graves de esta enfermedad que los puede conducir a la muerte. Estudios resientes corroboran la relación de esta infección con trastornos neurosiquiatricos, en particular con la esquizofrenia, así como su relación con accidentes de tránsito en conductores seropositivos; es de gran importancia tener presente las formas de adquirir la enfermedad y las medidas de precaución sobre todo cuando se ha demostrado que nunca se ha padecido la enfermedad.

One third of the world population have antibodies against Toxoplasma gondii. Human beings may be infected by sporozoites from cat faeces contaminating the ground, fruits, vegetables and water, by bradyzoites present in insufficiently cooked or improperly manipulated meat, or by trophozoites circulating during the hematogenous phase. Fetuses may be infected through the placenta, and seronegative individuals by solid organs transplanted or transfused with formed elements of the blood. These are the risk groups most prone to develop serious, life-threatening forms of the disease. Recent studies confirm the relationship of this infection to neuropsychiatric disorders, particularly schizophrenia, as well as its relationship to traffic accidents among seropositive drivers. It is paramount to bear in mind the ways in which the disease may be acquired and the corresponding prevention measures, especially for persons who have never had the disease.

Toxoplasmosis sistémica en un canguro rojo (Macropus rufus) cautivo / Systemic toxoplamosis in a captive red kangaroo (Macropus rufus)

Los objetivos del estudio fueron presentar y documentar los hallazgos histopatológicos de toxoplasmosis sistémica en un canguro rojo (Macropus rufus) mantenido en cautiverio donde se describen los hallazgos macro y microscópicos encontrados y los análisis adicionales realizados. En el laboratorio de histopatología animal (Universidad de los Llanos) se recibieron muestras de tejidos fijados en formol tamponado, al 10% que procedían de un ejemplar macho de Macropus rufus, de ocho años de edad y 50 kg de peso corporal. Las muestras se procesaron mediante métodos rutinarios para microscopía óptica. Los cortes histológicos de 3-4 mm de grosor se colorearon con Hematoxilina-Eosina (H&E) y se realizó en algunos cortes la tinción de Ácido Periódico Schiff (PAS), PCR e IHQ. Al análisis histopatológico se encontró una toxoplasmosis sistémica asociada a quistes de protozoarios con inmunoreactividad positiva para T. gondii. La detección de T gondii en tejidos en formalina fue hecha usando dos ensayos de PCR que señalaban segmentos de ADN de diferentes secuencias repetitivas encontradas en T gondii y la IHQ confirmo lo hallado por PCR. Histopatológicamente se diagnosticó infección crónica por protozoarios eucoccideos de la familia Sarcocystidae. El diagnóstico etiológico fue de toxoplasmosis.

The objetives of this study were to present and document the hystopathologycal findings of systemic toxoplamosis in a captive red kangaroo (Macropus rufus) which described macro and microscopic findings of the hystopathological analysis. In the laboratory of animal histopathology (Universidad de los Llanos) formalin fixed tissue specimens were received, from a captive male Macropus rufus, who was eight years old and weighed 50 kg. The samples were processed by usual methods for optical microscopy. The histological sections of 3-4 mm thick were colored with Hematoxilin-Eosin (H&E) and then some samples stained with Periodic Acid Schiff (PAS), and processed by PCR and IHQ. Once the histopathological analysis was performed systemic toxoplasmosis was associated to protozoa cysts immunoreactives to T. gondii. The molecular detection of T. gondii in formalin fixed tissues was made using two PCR tests and confirmated by IHQ. Histopathologically a chronic infection by an eucoccideo protozoa from the Sarcocystidae family was diagnosed. The etiologic diagnosis was toxoplasmosis.

Interaction and cystogenesis of Toxoplasma gondii within skeletal muscle cells in vitro

Infection by the protozoan parasite Toxoplasma gondii is widely prevalent in humans and animals. To prevent human infection, all meat should be well cooked before consumption, since the parasite is present in skeletal muscle. In this context, the use of skeletal muscle cells (SkMCs) as a cellular model opens up new approaches to investigate T. gondii-host cell interactions. Immunofluorescent detection of proteins that are stage-specific for bradyzoites indicated that complete cystogenesis of T. gondii in in vitro cultures of SkMCs occurs after 96 h of infection. Ultrastructural analysis showed that, after 48 h of interaction, there were alterations on the parasitophorous vacuole membrane, including greater thickness and increased electron density at the inner face of the membrane. The present study demonstrates the potential use of primary cultures of SkMCs to evaluate different molecular aspects of T. gondii invasion and cystogenesis and presents a promising in vitro model for the screening of drug activities toward tissue cysts and bradyzoites.

Toxoplasmic Lymphadenitis with Toxoplasma Bradyzoites: A Case Report

Toxoplasmic lymphadenitis is the most frequently observed clinical form of acquired toxoplasmosis. It is diagnosed by observing the characteristic histopathology, performing serologic tests and demonstrating the organisms. However, detection of the organisms in lymph node section is rarely accomplished. We demonstrate a case of a toxoplasmic lymphadenitis of a 40-year-old man with bradyzoites. The histopathologic findings of the lymph nodes showed reactive follicular hyperplasia associated with the presence of irregular clusters of epithelioid histiocytes, usually located in the cortical and paracortical zones, and monocytoid B cell proliferation. We demonstrated the bradyzoites of Toxoplasma gondii with periodic acid-Schiff (PAS)-stain, and serologic testing showed positive Ig-G and Ig-M toxoplasma antibodies.