Epidemiology
Earthworm transport hosts are important factors in the transmission of Syngamus trachea when poultry and game birds are reared on soil. The longevity of L3s in earthworms (up to 3 years) is particularly important in perpetuating the infection from year to year. Wild birds may serve as reservoirs of infection and have been implicated as the sources of infections in outbreaks on game-bird farms as well as poultry farms. Wild reservoir hosts may include pheasants, ruffed grouse, partridges, wild turkeys, magpies, meadowlarks, American robins, grackles, jays, jackdaws, rooks, starlings and crows. There is also evidence to suggest that strains of Syngamus trachea from wild bird reservoir hosts may be less effective in domestic birds; if they have an earthworm transport host rather than direct infections via ingestion of L3s, or eggs containing L3s. Clinical signs
Blockage of the bronchi and trachea with worms and mucus will cause infected birds to gasp for air. They stretch out their necks, open their mouths and gasp for air producing a hissing noise as they do so. This "gaping" posture has given rise to the common term "gapeworm" to describe Syngamus trachea. These clinical signs first appear approximately 1–2 weeks after infection. Birds infected with gapeworms show signs of weakness and emaciation, usually spending much of their time with eyes closed and head drawn back against the body. An infected bird may give its head a convulsive shake in an attempt to remove the obstruction from the trachea so that normal breathing may be resumed.
Prognosis is not strongly affected by staging in MCL and the concept of metastasis does not really apply.The Mantle Cell Lymphoma International Prognostic Index (MIPI) was derived from a data set of 455 advanced stage MCL patients treated in series of clinical trials in Germany/Europe. Of the evaluable population, approximately 18% were treated with high-dose therapy and stem cell transplantation in first remission. The MIPI is able to classify patients into three risk groups: low risk (median survival not reached after median 32 months follow-up and 5-year OS rate of 60%), intermediate risk (median survival 51 months) and high risk (median survival 29 months). In addition to the 4 independent prognostic factors included in the model, the cell proliferation index (Ki-67) was also shown to have additional prognostic relevance. When the Ki67 is available, a biologic MIPI can be calculated.MCL is one of the few NHLs that can cross the boundary into the brain, yet it can be treated in that event.There are a number of prognostic indicators that have been studied. There is not universal agreement on their importance or usefulness in prognosis.Ki-67 is an indicator of how fast cells mature and is expressed in a range from about 10% to 90%. The lower the percentage, the lower the speed of maturity, and the more indolent the disease. Katzenberger et al. Blood 2006;107:3407 graphs survival versus time for subsets of patients with varying Ki-67 indices. He shows median survival times of about one year for 61-90% Ki-67 and nearly 4 years for 5-20% Ki-67 index.