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Histomonosis (histomoniasis, blackhead), beside coccidiosis, belongs to the most important parasitic protozoan diseases in poultry. So far Histomonas meleagridis infections with varied mortality rates have been mainly diagnosed in young turkeys. Recently an increasing number of cases have been reported in chicken flocks in Europe resulting in economic losses. It is thought that this situation is predominantly caused by a complete withdrawal of the effective antihistomonals in the EU. Authors listed the selected outbreaks of histomonosis in 10 chicken flocks originated from different farms of 4 regions in Poland: 8 broiler breeder flocks (at mean age of 33 weeks) and 2 commercial layers flocks (at mean age of 38 weeks). This study reported here naturally occurring case of H.meleagridis infection in commercial broiler breeder (BB) flock line ROSS 308 at the age of 16 weeks. We showed acute form of infection with characteristic necrotic foci in the liver, and ulcerative typhilitis. Beside the liver and caeca, the multiple histomonads, lymphoid tissue depletion and heavy destruction in the bursa of Fabricius were observed. Additionally, the absence of systemic diffuse histomonads and lack of Heterakis gallinarum, caecal worm eggs in faecal samples were noted. PCR technique enabled to detect the presence of H.meleagridis genetic material in the investigated tissue samples. Authors indicate that histomonosis can be considered as re-emerging infectious diseases in chicken flocks of intensive production system.

The study was aimed at determining the cause of the diseases in three horses exhibiting symptoms of fever, ataxia, mucus membrane paleness, haematuria and thrombocytopenia. The PCR technique revealed the presence in the blood of 18S RNA Babesia/Theileria spp. genetic material. DNA amplification using primers RLB F2 and RLB R2 produced 430 bp size products. The sequences of these PCR products demonstrated a 95.6-97.5% similarity with the sequence of the fragment of 18S RNA Babesia equi, gene number DQ287951 in the GenBank. The treatment utilizing the subcutaneous application of the imidocarb resulted in gradual recovery of the diseased animals.

The studies were carried out in Kosewo Górne in the Mazurian District (North-East region of Poland), in September 1995, September 1996 and between May 1997 and June 1998 each month. The animals were trapped in live traps, and after study they were marked and released. The infection of trypanosomes was detected using microhaematocrit centrifugation technique and in blood smears. The intensity of infection had the range from 50 to 150 000 individuals in 1 ml of blood. The maximal prevalence of infection was in August and September and there were 45% and 38% of infected voles respectively. The infection was detected also in May 1998, in other months the prevalence had low level. There were no individuals of bank vole infected in succeeding months. The females of bank vole are more often infected with trypanosomes than males.