Israel Medical Association Journal

Background: Pertussis is the only vaccine-preventable disease that has re-emerged in Israel. The reported crude incidence of the disease increased 16-fold since 1998.

Objectives: To describe the epidemiology of pertussis and to explain the substantial increase in reported pertussis incidence in Israel in recent years.

Methods: Crude and specific pertussis incidence by age, patient immunization status, hospitalization rate and national immunization coverage rate were calculated from information provided by the public health offices of the Ministry of Health.

Results: The reported crude incidence of pertussis increased from 1–2/100,000 in 1994–98 to 23/100,000 in 2004. The trend was observed in all age groups, being most prominent in infants under age 1 year and in children aged 5–14. The incidence of pertussis was substantially higher in unvaccinated and partly vaccinated compared to fully vaccinated persons. Fifteen percent of notified cases were hospitalized, but in infants under age 1 year the hospitalization rate was 50%. National pertussis immunization coverage by age 2 years was stable during the last 10 years.

Conclusions: There are several possible explanations for the re-emergence of pertussis in Israel. The most plausible reason seems to be the waning of vaccine-induced immunity in face of infrequent natural exposure to the infectious agent and lack of a pertussis vaccine booster dose after age 1.
 

Background: Poliovirus rapidly evolves by nucleic acid substitutions and genetic recombination with other polioviruses and non-polio enteroviruses. Evolving oral poliovirus (Sabin strains) can rapidly revert to neurovirulence and undergo antigenic alterations.

Objectives: To evaluate the threat of vaccine-derived poliovirus (1–15% divergence from the respective Sabin strain) for a poliomyelitis-free population in a country with a long-standing routine vaccination program.

Methods: We characterized genetic and antigenic changes in OPV[1] strains isolated from sewage in Israel and evaluated intestinal immunity by measuring fecal excretion after OPV challenge of vaccinated children.

Results: Characterization of poliovirus from sewage revealed eight type 2 and three type 3 vaccine polioviruses that had replicated and started to evolve (vaccine that replicated and diverged by 0.5 to ≤ 1.0%) and nine highly diverged type 2 vaccine-derived polioviruses (1–15% divergence from the respective Sabin strain) with 8–14% divergence between the years 1998 and 2005. Six of the eleven VRPV[2] uniquely recombined with OPV and/or NPEV[3]. The nine VDPV[4] were epidemically related, genotypically neurovirulent, and had 10–15 amino acid substitutions in antigenic sites altering their antigenicity, but shared a single recombination. Type 2 OPV was excreted by 23% and 17% of infants challenged with OPV 3 months after partial immunization (two doses each of OPV and enhanced inactivated poliovirus) or full immunization (three doses of each) respectively, despite high humoral antibody titers.

Conclusions: Our findings, which show that OPV is excreted for a significant period by children with high humoral immunity, emphasize the long-term potential threat from VDPV in highly vaccinated populations. An adequate immunization program, combined with environmental surveillance, is necessary to prevent poliomyelitis and community transmission of poliovirus. 

Background: The co-morbidity of human immunodeficiency virus and other sexually transmitted diseases in Israel has not been established. 

Objectives: To compare the prevalence of STDs [1]among HIV[2]-positive patients to HIV-negative patients visiting an STD clinic in northern Israel. 

Methods: Between December 2000 and December 2001, 176 HIV-positive individuals (53% males) were screened and compared to 200 HIV-seronegative individuals (76% males). Demographics, symptomatology and risk factors were obtained via questionnaire. First-void urine samples were tested for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae. Serum was tested for type-specific herpes simplex virus-2, hepatitis B and syphilis. 

Results: Relative to the seronegative STD patients, HIV-positive patients exhibited significantly greater risk-reducing sexual behaviors such as consistent condom use [29/86 (33.7%) vs. 16/187 (8.6%), P < 0.001], and abstinence in the previous 6 months [43/125 (34%) vs. 7/185 (3.8%), P < 0.001]. Nevertheless, STD prevalence was higher among HIV-positive than HIV-negative patients (79.5% vs. 37.5%, P < 0.001). HSV[3]-2, syphilis and HBV[4] were more common among HIV-positive than HIV-negative patients [120/175 (68.8%)] vs. 18/200 (9%), P < 0.001)], [43/161 (26.7%) vs. 0%, P < 0.001)], [13/171 (7.6%) vs. 3/200 (1.5%), P < 0.01)], respectively. In contrast, Chlamydia and gonorrhea were more commonly found in HIV-negative patients than HIV-positive patients [3/176 (1.7%) vs.13/200 (6.5%), P < 0.05] vs. [0% vs.5/200 (2.5%), P < 0.05], respectively. 

Conclusion: Despite the low risk sexual behavior of Israeli HIV patients, they had a high prevalence of chronic STDs (e.g., HSV-2, HBV and syphilis). The lower prevalence of Chlamydia and gonorrhea among HIV-immunosuppressed patients may be attributed to routine antibiotic prophylaxis against opportunistic infections. Nevertheless, as advocated by international health organizations, it appears prudent to recommend the routine screening of these asymptomatic HIV-positive patients for STD pathogens. 

Background: Q fever is endemic in Israel, yet a large series describing the clinical spectrum of inpatients with acute Q fever in Israel is lacking. 

Objectives: To report on the clinical characteristics and outcome of hospitalized patients with acute Q fever in Israel. 

Methods: We conducted a retrospective study of 100 patients hospitalized in six medical centers, in whom acute Q fever was diagnosed by the presence of immunoglobulin G and M antibodies to phase II Coxiella burnetti antigens. 

Results: The mean age of the patients was 42.7 ± 17.3 years with a male to female ratio of 1.6:1. Acute Q fever occurred throughout the year but was more common during the warm season. The most common clinical presentation was acute febrile disease (98%, mean length of fever 15.5 ± 8.6 days), followed by hepatitis (67%) and pneumonia (32%). The prominent laboratory findings included: accelerated erythrocyte sedimentation rate, normal or low white blood count with many band forms, thrombocytopenia, and abnormal urinalysis. Although the diagnosis of acute Q fever was not known during the hospitalization in the majority of patients, about 80% of our patients received appropriate antibiotic therapy and all patients recovered. 

Conclusions: Patients with acute Q fever present with a typical clinical picture that enables clinical diagnosis and empiric therapy in most cases. The prognosis of hospitalized patients with acute Q fever is excellent.

The Ashkenazi-Jewish population is at increased risk for several recessively inherited disorders. While some of the disorders have severe or fatal symptom manifestations, others, such as non-neuronopathic Gaucher disease, do not usually pose a serious, life-threatening illness. Many healthcare centers in Israel offer prenatal panel screening. Controversy exists over the inclusion of Gaucher disease in the panel screening, especially since Gaucher disease screening lacks prognostic reliability. Most screening participants do not discriminate between the specific tests in the panel and are unable to discern between severe, life-threatening diseases and those that are less severe and even treatable. By including screening for Gaucher in the panel screening program, there is risk of a "panel effect," leading to termination of a pregnancy positive for Gaucher disease, without sufficient knowledge and understanding of the disease. Increasing medical and public awareness and knowledge of the disease, its prognosis and treatment options may reduce the rate of under-informed abortions associated with prenatal screening of Gaucher disease.

Polyubiquitylation of cellular proteins has long been recognized as a prelude to a degradative fate in proteasomes. In recent years, however, ubiquitin conjugation has emerged as a regulatory strategy of considerable versatility. Most notably, monoubiquitylation is attributed an intimate role in trafficking of membrane proteins between various cellular compartments. Diverse classes of transmembrane proteins from across the eukaryotic spectrum (e.g., epidermal growth factor-receptor and other receptor tyrosine kinases) become modified with monoubiquitin molecules. Monoubiquitylation of substrates, in turn, regulates both their endocytosis at the plasma membrane and sorting in endosomes for delivery to lysosomes or vacuoles. A mechanistic rationale lies in the identification of a growing list of ubiquitin-binding domains carried by a variety of endocytic adaptor proteins. Thus, ubiquitin-conjugated membrane proteins may form extensive contacts with the endocytic machinery. Further, ubiquitin-binding adaptors and other endocytic components are, likewise, often monoubiquitylated. In this case, ubiquitin conjugation may serve to enhance intermolecular avidity in cargo-bound endocytic complexes, or alternatively, to mediate timely inactivation of ubiquitin-binding adaptors. Interestingly, the ubiquitin/endocytosis interface is appropriated by pathogenic organisms, for instance, during budding of viruses from host-infected cells. Moreover, compromised ubiquitin-mediated transport of certain signaling receptors is associated with disease states, including oncogenic transformation.

We describe a unique E3, the F-box protein, Ufo1, of yeast. Ufo1 recruits the mating switch endonuclease, Ho, to the SCF complex for ubiquitylation. In addition to the F-box and WD40 protein-protein interaction domains found in all F-box proteins, Ufo1 has a unique domain comprising multiple copies of the ubiquitin-interacting motif. Ufo1 interacts with the UbL-UbA protein, Ddi1, via its UIMs[1], and this is required for turnover of SCF ^Ufo1 complexes. This is a novel function for an UbL-UbA protein. Deletion of the genomic UFO1 UIMs is lethal and our data indicate that Ufo1ΔUIM acts as a dominant negative leading to inhibition of the SCF pathway of substrate degradation and to cell cycle arrest. Furthermore, we found that Ddi1 is required for the final stages of degradation of Ho endonuclease. In the absence of Ddi1, Ho does not form a complex with the 19S RP and is stabilized. Stabilization of Ho leads to perturbation of the cell cycle and to the formation of multi-budded cells. Our experiments uncover a novel role for the ubiquitin-proteasome system in maintenance of genome stability.

The Ink4a-Arf locus, which encodes two distinct tumor suppressor proteins, is inactivated in many cancers. Whereas p16^Ink4a is an inhibitor of cyclin D-dependent kinases, p19^Arf (p14^ARF in humans) antagonizes the E3 ubiquitin protein ligase activity of Mdm2 to activate p53. We now recognize that Arf functions in both p53-dependent and -independent modes to counteract hyper-proliferative signals originating from proto-oncogene activation, but its p53-independent activities remain poorly understood. Arf proteins are highly basic (> 20% arginine content, pI > 12) and predominantly localize within nucleoli in physical association with an abundant acidic protein, nucleophosmin (NPM/B23). When bound to NPM[1], Arf proteins are relatively stable with half-lives of 6–8 hours. Although mouse p19^Arf contains only a single lysine residue and human p14^ARF has none, both proteins are N-terminally ubiquitinated and degraded in proteasomes. Through as yet uncharacterized mechanisms, p19^Arf induces p53-independent sumoylation of a variety of cellular target proteins with which it interacts, including both Mdm2 and NPM. A naturally occurring NPM mutant (NPMc) expressed in myeloid leukemia cells redirects both wild-type NPM and p19^Arf to the cytoplasm, inhibits Arf-induced sumoylation, and attenuates p53 activity. Thus, ubiquitination and sumoylation can each influence Arf tumor suppressor activity.