Co-infection with multiple different parasites is a common phenomenon in both human and animals. Among parasites that frequently co-infect the same hosts, are the filarial worms and malaria parasites. Despite this, the mechanisms underlying the interactions between these parasites is still relatively unexplored with very few studies available on the resulting pathologies due to co-infection by filarial nematodes and malaria parasites. Hence, this study investigated the histopathological effect of Brugia pahangi and Plasmodium berghei ANKA (PbA) infections in gerbil host. Gerbils grouped into B. pahangi-infected, PbA-infected, B. pahangi and PbA-coinfected, and uninfected control, were necropsied at different time points of post PbA infections. Brugia pahangi infections in the gerbils were first initiated by subcutaneous inoculation of 50 infective larvae, while PbA infections were done by intraperitoneal injection of 106 parasitized red blood cells after 70 days patent period of B. pahangi. Organs such as the lungs, kidneys, spleen, heart and liver were harvested aseptically at the point of necropsy. There was significant hepatosplenomegaly observed in both PbA-infected only and coinfected gerbils. The spleen, liver and lungs were heavily pigmented. Both B. pahangi and PbA infections (mono and coinfections) resulted in pulmonary edema, while glomerulonephritis was associated with PbA infections. The presence of both parasites induced extramedullary hematopoiesis in the spleen and liver. These findings suggest that the pathologies associated with coinfected gerbils were synergistically induced by both B. pahangi and PbA infections.
Extramedullary hematopoiesis (EH) is a rare but well-known compensatory mechanism of red blood cell production when the normal site of red bone marrow is unable to produce sufficient number of red blood cells. When the body demands for erythrocyte cells is high this lead to EH. This occurs mainly outside the bone marrow, usually paraspinally and sites which are normally observed in the fetus as in the liver, spleen, lymph nodes and less frequently at other sites such as adrenal, thymus, kidneys, pleura, breast, skin, gastrointestinal tract, dura mater and brain.This is more frequent in thalassaemia major (incidence up to 15% of cases), in myelofibrosis, myeloproliferative diseases (polycythemia rubra vera, chronic myeloid leukemia,), hemolytic anemias such as hereditary spherocytosis, pyruvate-kinase deficiency, medullary tuberculosis and in Paget’s disease of the bone. In some cases the cause of the EH are not identified [3]. We describe a case of EH in the presacral space that mimicked an ovarian mass on ultrasound in a patient with beta-thalassaemia intermedia.