Chickens treated with a nitric oxide inhibitor became more resistant to Plasmodium gallinaceum infection due to reduced anemia, thrombocytopenia and inflammation

Abstract

Malaria is a serious infectious disease caused by parasites of the Plasmodium genus that affect different vertebrate hosts. Severe malaria leads to host death and involves different pathophysiological phenomena such as anemia, thrombocytopenia and inflammation. Nitric oxide (NO) is an important effector molecule in this disease, but little is known about its role in avian malaria models. Plasmodium gallinaceum- infected chickens were treated with aminoguanidine (AG), an inhibitor of inducible nitric oxide synthase, to observe the role of NO in the pathogenesis of this avian model. AG increased the survival of chickens, but also induced higher parasitemia. Treated chickens demonstrated reduced anemia and thrombocytopenia. Moreover, erythrocytes at different stages of maturation, heterophils, monocytes and thrombocytes were infected by Plasmodium gallinaceum and animals presented a generalized leucopenia. Activated leukocytes and thrombocytes with elongated double nuclei were observed in chickens with higher parasitemia; however, eosinophils were not involved in the infection. AG reduced levels of hemozoin in the spleen and liver, indicating lower inflammation. Taken together, the results suggest that AG reduced anemia, thrombocytopenia and inflammation, explaining the greater survival rate of the treated chickens.

Plasmodium spp. and Haemoproteus spp. infection in birds of the Brazilian Atlantic Forest detected by microscopy and polymerase chain reaction

“…In birds, these parasites, has been described as a potential cause of extinction and population decline (Van Riper III et al 1986, Atkinson et al 1995, Massey et al 1996, reducing the fitness of their hosts (Lefèvre et al 2008) and may sometimes lead to death (Donovan et al 2008, Cannell et al 2013. Severe infections by haemosporidian can lead to death and involves different physiopathological phenomena such as anemia, thrombocytopenia and inflammation (Macchi et al 2013, Cannell et al 2013). …”

Exposing migratory sparrows to Plasmodium suggests costs of resistance, not necessarily of infection itself

“…Exposure to parasites represents an additional challenge at this key stage in the annual cycle. Individuals that become infected experience direct physiological costs; for example, hematozoa damage blood cells and other tissues (Booth & Elliott, ; de Macchi et al., ). However, even individuals that successfully resist infection may incur energetic and inflammatory costs when mounting an immune response (Klasing, ; Lochmiller & Deerenberg, ).…”

“…Haemosporidians of genera Plasmodium and Haemoproteus , associated with avian malaria, have been implicated in extinctions and severe population declines in many bird species (Warner, ; Van Riper III et al., ). Such infections can induce muscle wasting, anemia, fever, organ damage, and inflammation in their avian hosts (Booth & Elliott, ; de Macchi et al., ), particularly during the first few weeks of infection corresponding to the acute, or primary, phase. In extreme cases, these infections can result in the death of the host individual (de Macchi et al., ; Ilgūnas et al., ), but otherwise subside to chronic‐phase infections associated with lower parasite burdens that may persist for months or years following initial infection (Asghar et al., ).…”

Aspectos morfológicos e ultraestruturais de células sanguíneas de Crotalus durissus terrificus

“…No estudo atual, dez (10) dos cinquenta e dois (52) espécimes avaliados estavam parasitados por hemoparasitas do gênero Hepatozoon e outros dois pelo gênero Plasmodium. O parasito do gênero Plasmodium foi confirmado pelo método de polarização em que seu pigmento apresentou birrefringência (De Macchi et al 2013). Embora protozoários do gênero Hepatozoon seja frequentemente observado em esfregaços sanguíneos de serpentes acredita-se que em condições de estresse eles possam acarretar anemias de intensidade variável (Almosny 2014).…”