Prevalence and risk factors associated with Tritrichomonas foetus infection in cattle in the state of Paraíba, Brazil
The objective of this study was to determine the prevalence of Tritrichomonas foetus infection and to evaluate risk factors associated with this infection among cattle in the state of Paraiba in northeastern Brazil. Samples of cervicovaginal mucus from 290 females and smegma from 59 males [beef, 31; mixed aptitude (beef and dairy), 10; and dairy, 18] from 31 farms were collected. Modified Diamond’s medium and polymerase chain reaction (PCR) were used for the laboratory diagnosis of T. foetus infection. Univariate analysis and logistic regression were performed to test for potential risk factors in addition to prevalence mapping. No sample was positive for T. foetus in culture, and the prevalence of T. foetus infection using PCR was 3.7% (13/349) [confidence interval (CI) 95%, 2.1%–6.4%]. In total, 19.3% (6/31) of the farms had at least one animal positive for T. foetus. The contact of females with males from other farms [Odds ratio, 5.9; 95% CI, 1.5–22.4; p = 0.009] was identified as a risk factor for T. foetus infection. This study demonstrates that T. foetus infection is prevalent among dairy cows in the state of Paraiba, Brazil. Sexual resting, removal of positive females, and avoiding contact of females with males from other farms are recommended to reduce the risk of infection.
In Vitro Susceptibility to Metronidazole of Tritrichomonas foetus Bovine Isolates from Argentina
BackgroundTritrichomonas foetus is the etiologic agent of the sexually transmitted disease Bovine Trichomonosis (BT). In Argentina, BT is endemic and represents a relevant health problem that causes reproductive inefficiency in cattle and large economic losses. Metronidazole is the drug of choice in the treatment of BT. Treatment has been associated with a temporary resolution of the clinical signs but is not able to control the disease. In recent years, the apparition of in vivo and in vitro aerobic and anaerobic resistance leading to ineffective treatments has been reported.AimsThus, the aim of the present study was to explore the susceptibility of six different isolates of T. foetus under aerobic (AC) and anaerobic (ANC) conditions.Results and discussionSix isolates of T. foetus were obtained from samples of preputial smegma of bovine origin. Values of minimum lethal concentration and minimum inhibitory concentration were higher than those observed in other works and represent current data in Argentina and provide information to establish new treatment protocols.
The infection process, sporulation and survival of Alternaria helianthi on sunflower
SUMMARY 
 
Electron microscopy was used to study the infection of sunflower leaves by Alternaria helianthi. Conidia germinated by producing one to many germ tubes which grew across the leaf surface before forming appressoria. The fungus directly penetrated its host through the cuticle and epidermis. Entry into the host through wounds and stomates was also observed. Extracellular sheaths were found to be associated with germ tubes and intercellular hyphae of A. helianthi. Conidiophores developed through collapsed stomates, from leaf veins, trichomes and also from mycelium growing across the host leaf surface. Microcylic conidia were produced directly from parent conidia under certain conditions. Studies using a volumetric spore trap showed that the airborne spore concentration followed a distinct periodicity with peaks occurring between 0900 and 1100 h each day. Laboratory studies showed that safflower, noogoora burr and bathurst burr could serve as alternative hosts for A. helianthi. The pathogen was readily isolated from sunflower crop debris from a diseased crop that had been harvested 1 yr earlier.