Hepatitis A virus subgenotypes in Latvia, 2008-2021

BACKGROUND

In Latvia outbreaks of the HAV were observed between 2008 and early 2010 and again in 2017-2018. However, the risks of introducing and spreading infection still exist, as the virus spreads easily when personal hygiene is not followed.

METHODS

To determine the spread of HAV subgenotypes in the territory of Latvia the VP1/P2A genomic region of HAV was amplified and sequenced for 259 case serum samples. The study carried out a molecular biological investigation and molecular epidemiological investigation. Demographic data (sex, age), disease data (hepatitis symptoms, hospitalization, vaccination) and epidemiology data (part of the outbreak, possible source of infection, recent travel) were collected. Based on the obtained sequences, the phylogenetic tree was built and analyzed for the homology and belonging to different isolated HAV clusters from other countries.

RESULTS

From the obtained data, it was concluded that HAV subgenotype IA had 13 clusters and 12 sporadic cases, HAV subgenotype IB had eight clusters and 11 sporadic cases, HAV subgenotype IIIA had one cluster and nine sporadic cases. It was found that the sources of infection among the investigated cases were different, they were mostly associated with contact with a patient with HAV, travel, as well as between persons who inject drugs and men who have sex with men, and the prevalence of HAV similar sequences was observed in different years. It was concluded that patients with HAV subgenotype IA had the longest hospitalization duration and averaged 9.3 days, while patients with subgenotype IB - 7.3 days, subgenotype IIIA - 7.7 days. Analyzing the data on vaccination, it was found that mostly all were not vaccinated or had an unknown vaccination status.

CONCLUSIONS

All of this has led to the conclusion that the application of molecular biological methods of the HAV and a careful analysis of epidemiological data can help to better understand the ways of spreading the infection, investigate local outbreaks, detect cases of imported infection and track the recirculation of the virus.

1235. Anti-HCV Prevalence and Associated Risk Factors in Patients of Psychiatry Hospitals in Latvia

Background

According to previous epidemiological studies there is 2.4% prevalence of anti-HCV in Latvian population. Hepatitis C can lead to liver cirrhosis and HCC. There is available an effective HCV treatment with 100% reimbursement. WHO has settled a goal – to eliminate HCV as a public health threat by 2030. The biggest obstacle to achieve this goal is to find an infected persons.

The aim of this study was to screen and analyze the data of patients from Psychiatry hospitals (PH) in Latvia. Patients were screened for hepatitis C infection (anti-HCV) and analyze the possible risk factors.

Methods

795 patients of all PH in Latvia were tested, including 57.1% males and 42.9% females. The mean age was 49 years (range 18 - 93). Data were obtained by performing survey and rapid blood antibody tests. The questionnaire included demographic information and 10 questions on infection risk factors. Study was done from May till October 2021 by HIV Prevention Point workers in PHs of 7 PH in Latvia – Riga, Daugavpils, Liepaja, Strenci, Gintermuiza, Akniste and Vecpiebalga. Data were analyzed using MS Excel and IBM SPSS.

Results

24.8% of patients noted they have been sexually active in the last year, but only 9.9% admitted usage of condoms. 3.8% noted they are or have been used IV drugs. 11.2% of patients have a history of incarceration.

In total 6.8% of performed tests were positive for anti-HCV. Incarcerated persons were positive in 16% of cases, non-incarcerated – in 6%. IV drug users (IVDU) were positive in 49%, non-users – in 4.9%, all differences are statistically significant.

Conclusion

Patients in PH are at higher risk of HCV infection in comparison to population in Latvia. Besides already well known risk groups – IVDU and incarcerated people, we found 2.8 times higher anti-HCV prevalence in psychiatric hospital’s patients, with markedly higher prevalence in those previously incarcerated or IVDU. This study provides valuable data to better identify groups of individuals with higher risk of HCV infection. Latvia. PNC patients should further be tested, especially individuals who have been incarcerated, use or have used IV drugs.

Disclosures

All Authors: No reported disclosures.

Intriguing findings of liver fibrosis following COVID-19

Background

Studies on a new coronavirus disease (COVID-19) show the elevation of liver enzymes and liver fibrosis index (FIB-4) independently on pre-existing liver diseases. It points to increased liver fibrogenesis during acute COVID-19 with possible long-term consequences. This study aimed to assess liver fibrosis in COVID-19 patients by serum hyaluronic acid (HA) and FIB-4.

Methods

The study included the acute COVID-19 group (66 patients, 50% females, mean age 58.3 ± 14.6), the post-COVID group (58 patients in 3–6 months after the recovery, 47% females, mean age 41.2 ± 13.4), and a control group (17 people, 47% females, mean age 42.8 ± 11.0). Ultrasound elastography was performed in the post-COVID and control groups.

Results

Sixty-five percent of the acute COVID-19 group had increased FIB-4 (> 1.45), and 38% of patients had FIB-4 ≥ 3.25. After matching by demographics, 52% of acute COVID-19 and 5% of the post-COVID group had FIB-4 > 1.45, and 29% and 2% of patients had FIB-4 ≥ 3.25, respectively. Increased serum HA (≥ 75 ng/ml) was observed in 54% of the acute COVID-19 and 15% of the post-COVID group. In the acute COVID-19 group, HA positively correlated with FIB-4, AST, ALT, LDH, IL-6, and ferritin and negatively with blood oxygen saturation. In the post-COVID group, HA did not correlate with FIB-4, but it was positively associated with higher liver stiffness and ALT.

Conclusion

More than half of acute COVID-19 patients had increased serum HA and FIB-4 related to liver function tests, inflammatory markers, and blood oxygen saturation. It provides evidence for the induction of liver fibrosis by multiple factors during acute COVID-19. Findings also indicate possible liver fibrosis in about 5% of the post-COVID group.

Incidence of cancer and overall risk of mortality in individuals treated with raltegravir-based and non-raltegravir-based combination antiretroviral therapy regimens

Objectives

There are currently few data on the long‐term risk of cancer and death in individuals taking raltegravir (RAL). The aim of this analysis was to evaluate whether there is evidence for an association.

Methods

The EuroSIDA cohort was divided into three groups: those starting RAL‐based combination antiretroviral therapy (cART) on or after 21 December 2007 (RAL); a historical cohort (HIST) of individuals adding a new antiretroviral (ARV) drug (not RAL) to their cART between 1 January 2005 and 20 December 2007, and a concurrent cohort (CONC) of individuals adding a new ARV drug (not RAL) to their cART on or after 21 December 2007. Baseline characteristics were compared using logistic regression. The incidences of newly diagnosed malignancies and death were compared using Poisson regression.

Results

The RAL cohort included 1470 individuals [with 4058 person‐years of follow‐up (PYFU)] compared with 3787 (4472 PYFU) and 4467 (10 691 PYFU) in the HIST and CONC cohorts, respectively. The prevalence of non‐AIDS‐related malignancies prior to baseline tended to be higher in the RAL cohort vs. the HIST cohort [adjusted odds ratio (aOR) 1.31; 95% confidence interval (CI) 0.95–1.80] and vs. the CONC cohort (aOR 1.89; 95% CI 1.37–2.61). In intention‐to‐treat (ITT) analysis (events: RAL, 50; HIST, 45; CONC, 127), the incidence of all new malignancies was 1.11 (95% CI 0.84–1.46) per 100 PYFU in the RAL cohort vs. 1.20 (95% CI 0.90–1.61) and 0.83 (95% CI 0.70–0.99) in the HIST and CONC cohorts, respectively. After adjustment, there was no evidence for a difference in the risk of malignancies [adjusted rate ratio (RR) 0.73; 95% CI 0.47–1.14 for RALvs. HIST; RR 0.95; 95% CI 0.65–1.39 for RALvs. CONC] or mortality (adjusted RR 0.87; 95% CI 0.53–1.43 for RALvs. HIST; RR 1.14; 95% CI 0.76–1.72 for RALvs. CONC).

Conclusions

We found no evidence for an oncogenic risk or poorer survival associated with using RAL compared with control groups.

Genetic variation spectrum in ATP7B gene identified in Latvian patients with Wilson disease

Background

Wilson disease (WD) is an autosomal recessive disorder of copper metabolism caused by allelic variants in ATP7B gene. More than 500 distinct variants have been reported, the most common WD causing allelic variant in the patients from Central, Eastern, and Northern Europe is H1069Q.

Methods

All Latvian patients with clinically confirmed WD were screened for the most common mutation p.H1069Q by PCR Bi‐PASA method. Direct DNA sequencing of gene ATP7B (all 21 exons) was performed for the patients with WD symptoms, being either heterozygous for H1069Q or without it on any allele.

Results

We identified 15 different allelic variants along with eight non‐disease‐causing allelic variants. Based on the gene molecular analysis and patients' clinical data variant p.His1069Gln was found in 66.9% of WD alleles. Wide clinical variability was observed among individuals with the same ATP7B genotype. The results of our study confirm that neurological manifestations of WD are typically present later than the liver disease but no significant association between the presence/absence of the most common genetic variant and mode of initial WD presentation or age at presentation was identified.

Conclusions

(1) The most prevalent mutation in Latvian patients with Wilson disease was c.3207C>A (p.His1069Gln); (2) No significant phenotype–genotype correlation was found in Latvian patients with Wilson disease; (3) The estimated prevalence of Wilson disease in Latvia is 1 of 24,000 cases which is higher than frequently quoted prevalence of 1: 30,000.

The present and future disease burden of hepatitis C virus infections with today's treatment paradigm - volume 3

The total number, morbidity and mortality attributed to viraemic hepatitis C virus (HCV) infections change over time making it difficult to compare reported estimates from different years. Models were developed for 15 countries to quantify and characterize the viraemic population and forecast the changes in the infected population and the corresponding disease burden from 2014 to 2030. With the exception of Iceland, Iran, Latvia and Pakistan, the total number of viraemic HCV infections is expected to decline from 2014 to 2030, but the associated morbidity and mortality are expected to increase in all countries except for Japan and South Korea. In the latter two countries, mortality due to an ageing population will drive down prevalence, morbidity and mortality. On the other hand, both countries have already experienced a rapid increase in HCV-related mortality and morbidity. HCV-related morbidity and mortality are projected to increase between 2014 and 2030 in all other countries as result of an ageing HCV-infected population. Thus, although the total number of HCV countries is expected to decline in most countries studied, the associated disease burden is expected to increase. The current treatment paradigm is inadequate if large reductions in HCV-related morbidity and mortality are to be achieved.

Strategies to manage hepatitis C virus infection disease burden - volume 3

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 15 countries in Europe, the Middle East and Asia, and the relative impact of two scenarios was considered: increased treatment efficacy while holding the annual number of treated patients constant and increased treatment efficacy and an increased annual number of treated patients. Increasing levels of diagnosis and treatment, in combination with improved treatment efficacy, were critical for achieving substantial reductions in disease burden. A 90% reduction in total HCV infections within 15 years is feasible in most countries studied, but it required a coordinated effort to introduce harm reduction programmes to reduce new infections, screening to identify those already infected and treatment with high cure rate therapies. This suggests that increased capacity for screening and treatment will be critical in many countries. Birth cohort screening is a helpful tool for maximizing resources. Among European countries, the majority of patients were born between 1940 and 1985. A wider range of birth cohorts was seen in the Middle East and Asia (between 1925 and 1995).

Historical epidemiology of hepatitis C virus (HCV) in select countries - volume 3

Detailed, country-specific epidemiological data are needed to characterize the burden of chronic hepatitis C virus (HCV) infection around the world. With new treatment options available, policy makers and public health officials must reconsider national strategies for infection control. In this study of 15 countries, published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates were gathered from the literature and validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Iran and Lebanon to 4.2% in Pakistan. The largest viraemic populations were in Pakistan (7 001 000 cases) and Indonesia (3 187 000 cases). Injection drug use (IDU) and a historically unsafe blood supply were major risk factors in most countries. Diagnosis, treatment and liver transplant rates varied widely between countries. However, comparison across countries was difficult as the number of cases changes over time. Access to reliable data on measures such as these is critical for the development of future strategies to manage the disease burden.

Phylogenetic analysis of the Latvian HIV-1 epidemic

The Latvian HIV-1 outbreak among intravenous drug users (IDUs) in 1997-1998 involved subtype A1. To obtain a more complete picture of the Latvian HIV-1 epidemic, 315 HIV-1-infected patients diagnosed in 1990-2005 representing different transmission groups and geographic regions were phylogenetically characterized using env V3 and gag p17 sequences. Subtypes A1 and B infections were found in 76% and 22% of the patients, respectively. The subtype A1 sequences formed one large cluster, which also included sequences from other parts of the former Soviet Union (FSU), whereas most subtype B sequences formed three distinct clusters. We estimated that subtype A1 was introduced from FSU around 1997 and initially spread explosively among IDUs in Riga. A recent increase of heterosexually infected persons did not form a separate subepidemic, but had multiple interactions with the IDU epidemic. Subtype B was introduced before the collapse of the Soviet Union and primarily has spread among men who have sex with men.

Increase of cases of legionellosis in Latvia, 2011

An increased number of legionellosis cases in 2011 has been reported in Latvia, compared to the ten previous years. A total of 30 legionellosis cases (1.35 per 100,000 inhabitants), including 19 females, have been confirmed until the end of September 2011. The majority of cases (n=23) were inhabitants of the capital city Riga. The reason for the increase in legionellosis is unclear. Twenty-six of the 30 cases are not travel-related.

Increase of cases of legionellosis in Latvia, 2011

An increased number of legionellosis cases in 2011 has been reported in Latvia, compared to the ten previous years. A total of 30 legionellosis cases (1.35 per 100,000 inhabitants), including 19 females, have been confirmed until the end of September 2011. The majority of cases (n=23) were inhabitants of the capital city Riga. The reason for the increase in legionellosis is unclear. Twenty-six of the 30 cases are not travel-related.

Low prevalence of transmitted drug resistance among newly diagnosed HIV-1 patients in Latvia

Transmitted drug resistance (TDR) is a concern because it may reduce the efficacy of antiretroviral treatment. Plasma samples of 119 HIV-1-infected patients who were newly diagnosed at the Infectology Center of Latvia in 2005 and 2006 were analyzed by an in-house genotypic resistance assay to determine the prevalence of TDR in Latvia. TDR was identified using the WHO 2009 list of mutations for surveillance of TDR as implemented in the Stanford Calibrated Population Resistance tool. Neighbor-joining phylogenetic analyses were used to determine genetic subtype and investigate the relatedness of the sequences. Resistance testing was successful in 117 of 119 patients. The study population represented ∼20% of all patients that were diagnosed in Latvia in 2005 and 2006 and was well distributed between gender, transmission routes, and areas of residence. Four patients showed evidence of TDR, which represents a prevalence of TDR of 3.4% (95% CI: 0.9-8.5%). All four patients displayed single, but different resistance mutations (M46I, F53L, M41L, and G190A). All patients, except one, were predicted to respond well to standard first-line therapy in Latvia. The prevalence of TDR in Latvia was low, which partly may be due to the low proportion of HIV-1 patients who receive antiretroviral therapy. The results indicate that routine resistance testing in Latvia currently should be focused on patients who display treatment failure, rather than treatment naive patients.

The prevalence of viral hepatitis C in Latvia: a population-based study

BACKGROUND AND OBJECTIVE

Chronic viral hepatitis C (VHC) is one of the most discussed infectious diseases worldwide. The number of infected persons worldwide is approximately 170 million, and in Europe, it exceeds 9 million. The aim of this study was to determine the prevalence of antibodies to hepatitis C virus (anti-HCV prevalence) and prevalence of HCV viremia (HCV-RNA prevalence) in Latvia.

MATERIAL AND METHODS

A multistage randomized selection was used. A total of 42 primary care physicians (PCPs) were randomly selected from the register of PCPs from different regions of Latvia. From each PCP register, 60 subjects were selected (1651 individuals in total) and invited for the anti-HCV test with a screening method (ELISA). In case of positive results, antibodies were confirmed by the Western blot test, and all these subjects were tested for HCV-RNA by polymerase chain reaction.

RESULTS

Of the 1459 subjects tested, 57 were positive for anti-HCV (3.9%; 95% CI 3% to 5%); 35 of them were positive for anti-HCV with a confirmatory test (2.4%; 95% CI, 1.7% to 3.3%): 19 men and 16 women (3.8% and 1.7%, respectively; P=0.011). The results of HCV RNA test were positive in 25 subjects (1.7%; 95% CI, 1.2% to 2.5%): 15 men and 10 women (3% and 1% respectively, P=0.019).

CONCLUSIONS

The prevalence of anti-HCV and HCV-RNA in Latvia was found to be 2.4% and 1.7%, respectively. The prevalence of anti-HCV and HCV-RNA was higher in men than women.

Chronic hepatitis C: quantitative EPR analysis of nitrogen oxide and copper in patients' blood

Measurements of nitrogen oxide and copper in the blood of 57 patients with chronic viral hepatitis C was carried out before antiviral therapy by electron paramagnetic resonance on a Radiopan EPR spectrometer. The results indicate elevated levels of nitrogen oxide and copper in the blood of these patients in comparison with normal subjects. Comparison of these findings with the results of a previous analysis of redox status of patients with chronic viral hepatitis C indicate that this disease is characterized by a significant pro-oxidant shift in the realization of redox processes and disorders in the metal ligand homeostasis (at least as regards copper).

HIV drug resistance tendencies in Latvia

The treatment of HIV infection in Latvia by using highly active antiretroviral therapy (HAART) was started in 1996. The prevalence and tendencies of HIV drug resistance among treated and treatment-naive patients in Latvia in the years 2006-2007 were evaluated in this study. Data of HIV genotyping, performed in 132 HIV-1 infected during years 2006-2007 by TRUGENE HIV-1 genotyping assay (BayerHealthCare-diagnostics) are included in the study. Analysis of data showed that in the group of treatment-naive individuals majority carried wild type virus. Prevalence of resistance-associated mutations (RAMs) in the treatment-naive group according to IAS list was 28%. In most cases it was NRTI mutation A62V that is associated with multinucleoside resistance caused by Q151M, its effect in the absence of Q151M is not known. By many authors A62V is supposed to be a result of polymorphism in RT gene and is excluded from the list of resistance mutations. High prevalence of A62V is typical for HIV-1 subtype A. As majority of treatment-naive cases (89%) in this study were with HIV-1 subtypes A or AE, we excluded A62V mutation and estimated RAMs prevalence in group of treatment-naive HIV-infected individuals as 7%. Minor PI mutations were not included in analyses. In Europe published rates generally very between 5% and 15%. In the group of treatment-experienced HIV infected people 25/75 were with HIV-1 subtype B, the rest part--with non-B subtypes: A/AE (35/75), CRF-01AE (7/75), B/AE (4/75) and others. In treatment-experienced patients RAMs prevalence was estimated as 58.6%. Most frequently RAMs were found for nucleoside reverse transcriptase inhibitors (NRTI) (49.3%) followed by non-nucleoside reverse transcriptase inhibitors (NNRTI) (22.6%) and protease inhibitors (PI) (16%). In the group of NRTI mutations M184V (26/75; 34.6%), A62V (12/75; 16.0%) and T215Y (8/75; 10.6%), in NNRTI mutations K103N (10/75; 13.3%), G190S (6/75; 8.0%), in PI group mutations L90M (6/75; 8.0%) and M461/L (6/75; 8.0%) occurred most frequently. The following drug susceptibility was predicted according to the Trugen expert interpretations: in 33/75 (44%) patients no evidence of resistance, in 21/75 (28%) patients resistance to 1 drug class (NRTI--16/75, NNRTI--4/75, PI--1/75), in 17 patients (22.6%) resistance to 2 drug classes (NRTI+NNRTI--9/75, NRTI+PI--7/75, NNRTI+PI--1/75) and in 3/75 (4%) patients resistance to all 3 classes of drugs (NRTI+NNRTI+PI). We conclude, that prevalence of RAMs in treatment-naive HIV infected persons in Latvia is comparable with prevalence in Europe. The origin of predominated mutation A62V associated with NRTI at present is not clear. In more than half of treated HIV infected patients HIV resistance to at least one HAART class was predicted.

From clinical and biochemical to molecular genetic diagnosis of Wilson disease in Latvia

Wilson disease (WD) is an autosomal recessive disorder of copper metabolism characterized by hepatic and/or neurological damage. More than 300 mutations in the gene ATP7B causing this defect have been reported. The data on correlation between WD patient genotypes and clinical presentation are controversial. In this paper the results of ATP7B mutation analysis by testing for mutation H1069Q and direct sequencing of six exons together with the clinical data of 40 Latvian WD patients are presented. Two previously described and two novel mutations as well as one previously reported polymorphism were identified. The H1069Q mutation was present at 52.5% of the disease alleles. One individual among 157 healthy Latvians was also found to be a mutation H1069Q carrier. The estimated incidence of WD in Latvia is approximately 1 in 25600. Wide clinical variability was observed among individuals with the same ATP7B genotype, thus supporting the suggestion that modifying factors play an additional role in the pathogenesis of WD. An algorithm for the diagnosis of WD, including testing for mutation H1069Q, is recommended for the populations where mutation H1069Q accounts for 50% of WD alleles or more.

Quality control assessment for the serological diagnosis of tick borne encephalitis virus infections

BACKGROUND

The diagnosis of tick borne encephalitis (TBE) is mainly based on the demonstration of specific antibodies in serum when neurological disease is manifested. Improving diagnostics is the most important step in detecting and dealing with these pathogens. Quality control measures are essential for TBE diagnosis.

OBJECTIVE

To assess an external quality assurance (EQA) program for the serologic diagnosis of TBE infections.

STUDY DESIGN

A panel of 12 serum samples was sent out to be tested for the presence of TBE virus-specific IgM and IgG. This panel contained seven TBE-positive samples for IgM and/or IgG; three negative samples; two samples positive either for West Nile virus (WNV) or Dengue virus (DENV).

RESULTS

Fourty-two laboratories from 25 European and 2 non-European countries participated in this EQA. The correct answer by each laboratory for all samples ranked between 58 and 96% and sera with IgM antibody positive for TBE were correctly recognized by 46-88% of the laboratories. Sera with IgG antibody positive for TBE were correctly recognized by 83-95% of the laboratories. False TBE-positive results were obtained with DENV, WNV or negative sera only for IgG-based assays.

CONCLUSION

Correct results for at least 90% of the samples were obtained by 33 of 40 participating laboratories for IgM and for 16 of 42 laboratories for IgG.

Clinical features of double infection with tick-borne encephalitis and Lyme borreliosis transmitted by tick bite

BACKGROUND

In Latvia and other endemic regions, a single tick bite has the potential to transmit both tick-borne encephalitis (TBE) and Lyme borreliosis.

OBJECTIVE

To analyse both the clinical features and differential diagnosis of combined tick-borne infection with TBE and Lyme borreliosis, in 51 patients with serological evidence, of whom 69% had tick bites.

RESULTS

Biphasic fever suggestive of TBE occurred in 55% of the patients. Meningitis occurred in 92%, with painful radicular symptoms in 39%. Muscle weakness occurred in 41%; in 29% the flaccid paralysis was compatible with TBE. Only two patients presented with the bulbar palsy typical of TBE. Typical Lyme borreliosis facial palsy occurred in three patients. Typical TBE oculomotor disturbances occurred in two. Other features typical of Lyme borreliosis detected in our patients were distal peripheral neuropathy (n = 4), arthralgia (n = 9), local erythema 1-12 days after tick bite (n = 7) and erythema chronicum migrans (n = 1). Echocardiogram abnormalities occurred in 15.

CONCLUSIONS

Patients with double infection with TBE and Lyme borreliosis fell into three main clinical groups: febrile illness, 3 (6%); meningitis, 15 (30%); central or peripheral neurological deficit (meningoencephalitis, meningomyelitis, meningoradiculitis and polyradiculoneuritis), 33 (65%). Systemic features pointing to Lyme borreliosis were found in 25 patients (49%); immunoglobulin (Ig)M antibodies to borreliosis were present in 18 of them. The clinical occurrence of both Lyme borreliosis and TBE vary after exposure to tick bite, and the neurological manifestations of each disorder vary widely, with considerable overlap. This observational study provides no evidence that co-infection produces unusual manifestations due to unpredicted interaction between the two diseases. Patients with tick exposure presenting with acute neurological symptoms in areas endemic for both Lyme borreliosis and TBE should be investigated for both conditions. The threshold for simultaneous treatment of both conditions should be low, given the possibility of co-occurrence and the difficulty in ascribing individual neurological manifestations to one condition or the other.

Diphtheria with polyneuropathy in a closed community despite receiving recent booster vaccination

INTRODUCTION AND METHODS

We report 20 patients aged 18-24 years from Latvia with diphtheritic polyneuropathy. All lived in a closed community and 80% were known to have been fully vaccinated against diphtheria until at least 14 years old. Diphtheria antitoxin had been administered within 3 days of the onset of upper respiratory tract infection in 16 patients and 15 received antibiotics.

RESULTS

Neurological symptoms developed after a median of 43 days (range 35-58) compared to only 10 days in previous studies of unvaccinated patients. All showed evidence of mild limb polyneuropathy with electrophysiological evidence of polyneuropathy. Only 30% showed early bulbar abnormalities compared to the usual rate of over 95% in diphtheritic polyneuropathy. However, 45% had later bulbar deterioration coinciding with the limb polyneuropathy.

CONCLUSIONS

These patients show that an attenuated form of polyneuropathy of later onset, with less prominent early bulbar features, can occur in patients vaccinated against diphtheria according to schedule but living in a closed community in a country where diphtheria remains endemic.

Thymidine Analogue Mutation Profiles: Factors Associated with Acquiring Specific Profiles and their Impact on the Virological Response to Therapy

Background

Studies have suggested that HIV-1 may develop thymidine analogue mutations (TAMs) by one of two distinct pathways – the TAM1 pathway (including mutations 41L, 210W and 215Y) or the TAM2 pathway (including mutations 67N, 70R and 219E/Q) – under the pressure of a not fully suppressive thymidine-analogue-containing regimen.

Methods

Frozen plasma samples stored in the EuroSIDA repository were selected and sent to two central laboratories for genotypic analysis. We considered 733 patients with at least one genotypic test showing ≥1 TAMs (the first of these tests in chronological order was used). TAM1 and TAM2 genotypic profiles were defined in accordance with previous literature. Statistical modelling involved logistic regression and linear regression analysis for censored data.

Results

The observed frequencies of patterns classifiable as TAM1 or TAM2 profiles were markedly higher than the probabilities of falling into these classifications by chance alone. The chance of detecting a TAM2 profile increased by 25% per additional year of exposure to zidovudine. We found that mutations 67N and 184V were not associated with a particular TAM profile. In the presence of TAM2 profiles, the adjusted mean difference in the 6-month viral reduction was 0.96 log10 copies/ml (95% confidence interval: 0.20; 1.73) higher in patients who started stavudine-containing regimens instead of zidovudine-containing regimens.

Conclusions

This study provides evidence that the suggested TAM clustering is a real phenomenon and that it may be driven by which thymidine analogue the patients has used. In patients with TAM2-resistant viruses, stavudine appears to retain greater viral activity than zidovudine.

Rapid epidemic spread of HIV type 1 subtype A1 among intravenous drug users in Latvia and slower spread of subtype B among other risk groups

To investigate the rapid HIV epidemic in Latvia, 97 newly detected individuals were sampled in 2000-2001. To establish the molecular epidemiology we sequenced the env V3 and gag p17 regions of the HIV genome and compared them with reference sequences using phylogenetic analyses. As expected, the vast majority (n = 88; 91%) were intravenous drug users (IDUs) from the Riga region. Also, the majority of the investigated individuals (n = 93; 96%) were found to carry a subtype A1 virus that may have entered the Latvian IDU population several times. In addition, one IDU was infected with CRF03_AB and three other individuals, who had been infected through sexual contacts, carried subtype B virus. Thus, subtype A1 dominates the Latvian epidemic and is strongly associated with the IDU risk group. Although some spread of subtype A1 has occurred in the heterosexual group, subtype B dominates among homosexually and heterosexually infected individuals.