Adenovirus type 7 (Ad 7) is the serotype among the 36 recognized adenovirus types which most frequently has been associated with severe illness. Three different epidemic patterns of Ad 7 infection can be distinguished: 1) the first appears during the winter among infants with median age below two years, has characteristic symptoms of high fever and pneumonia and an outcome that may be fatal: 2) the second appears in the fall among children with median age seven years, has characteristic symptoms of high fever, pneumonia, abdominal symptoms and meningism and an outcome that is favorable; 3) and the third has been seen as acute respiratory disease among military recruits. In the United States, the last mentioned outbreaks require prophylaxis in the form of a live enteric-coated vaccine. DNA restriction site mapping demonstrated the occurrence of three distinct viral entities of Ad 7, which have been designated Ad 7 prototype, Ad 7a (the vaccine strain) and the Ad 7b genome type. In the present study, 36 isolates obtained from outbreaks with the first and the second epidemic patterns were analyzed by restriction endonucleases Bam HI and Sma I. All were identified as the newly recognized Ad 7b genome type. It is concluded that this genome type is responsible for a large portion of the severe infections caused by Ad 7. The epidemic nature of Ad 7 and the severe illness noted among infants indicate that vaccination of institutionalized infants could be considered during years when Ad 7 epidemics appear.

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Babesia microti is the primary causative agent of human babesiosis, an emerging pathogen that causes a malaria-like illness with possible fatal outcome in immunocompromised patients. The genome sequence of the B. microti R1 strain was reported in 2012 and revealed a distinct evolutionary path for this pathogen relative to that of other apicomplexa. Lacking from the first genome assembly and initial molecular analyses was information about the terminal ends of each chromosome, and both the exact number of chromosomes in the nuclear genome and the organization of the mitochondrial genome remained ambiguous. We have now performed various molecular analyses to characterize the nuclear and mitochondrial genomes of the B. microti R1 and Gray strains and generated high-resolution Whole Genome maps. These analyses show that the genome of B. microti consists of four nuclear chromosomes and a linear mitochondrial genome present in four different structural types. Furthermore, Whole Genome mapping allowed resolution of the chromosomal ends, identification of areas of misassembly in the R1 genome, and genomic differences between the R1 and Gray strains, which occur primarily in the telomeric regions. These studies set the stage for a better understanding of the evolution and diversity of this important human pathogen.

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Summary Forty-one patients receiving remission induction chemotherapy with vincristine, adriamycin and prednisolone (VAP) for high grade lymphoma or acute lymphoblastic leukaemia were entered into a double blind, placebo controlled trial of oral acyclovir prophylaxis against herpes simplex virus (HSV) infection. The dose of acyclovir was 200mg four times daily for the duration of chemotherapy (six weeks). Of the 40 evaluable patients, 20 were randomised to each arm. Prophylactic oral acyclovir significantly reduced the incidence of clinical HSV infection from 60% on placebo to 5% acyclovir (P<0.001), and the incidence of viral isolates from 70% on placebo to 5% on acyclovir (P<0.001).Herpetic infections are common in immunosuppressed patients with malignant diseases (Aston et al., 1972;Casazza et al., 1966;Lam et al., 1981;Meyers et al., 1980;Muller et al., 1972), and may be life threatening. The oral ulceration and stomatitis caused by HSV may be associated with significant morbidity. In the past year eight of 25 (32%) patients with non-Hodgkin's lymphoma, admitted to our oncology ward with pyrexia when neutropenic, had virologically confirmed HSV infections. Intravenous acyclovir has been shown in randomised, placebo controlled trials to be effective in the treatment of HSV infection in immunocompromised patients (Chou et al., 1981;Mitchell et al., 1981;Wade et al., 1982), and in the prophylaxis of HSV infection (Hann et al., 1983;Saral et al. 1981). A report of oral acyclovir prophylaxis in bone marrow transplant patients has shown a reduced incidence of HSV in those patients treated with acyclovir compared with placebo, without significant toxicity (Gluckman et al. 1983). The aim of this trial was to evaluate the efficacy of prophylactic oral acyclovir against HSV infections in lymphoma and leukaemia patients receiving remission induction chemotherapy, in a double blind placebo controlled trial. Patients and methodsForty-one patients with high grade non-Hodgkin lymphoma or acute lymphoblastic leukaemia who were to receive chemotherapy using the VAP regimen (Blackledge et al., 1980) (Vincristine 2mg intravenously weekly for six weeks, Adriamycin 60 mgm-2 intravenously fortnightly for three doses, and oral prednisolone at 50 mg day-1 for six weeks)were eligible for the trial. After obtaining informed consent patients were randomised to receive acyclovir 200mg four times daily or placebo tablets of identical appearance. The tablets commenced on the first day of chemotherapy and were prescribed for six weeks.Patients with non-Hodgkin lymphoma attended the outpatient clinic for examination and treatment each week, and those with acute leukaemia were inpatients for the duration of therapy. Throat swabs and blood samples for haematology, biochemistry and acyclovir levels were taken weekly. Blood for viral serology was taken every three weeks. At each outpatient visit patients were asked about oral symptoms and coldsores. Lesions present at the time of consultation were swabbed for viral culture and if applicable sa...