High exposure of West Nile virus in equid and wild bird populations in Spain following the epidemic outbreak in 2020

A cross-sectional study was conducted to assess the circulation and risk factors associated with West Nile virus (WNV) exposure in equine and wild bird populations following the largest epidemic outbreak ever reported in Spain. A total of 305 equids and 171 wild birds were sampled between November 2020 and June 2021. IgG antibodies against flaviviruses were detected by blocking enzyme-linked immunosorbent assay (bELISA) in 44.9% (109/243) and 87.1% (54/62) of unvaccinated and vaccinated equids, respectively. The individual seroprevalence in unvaccinated individuals (calculated on animals seropositive by both bELISA and virus microneutralization test [VNT]) was 38.3% (95%CI: 33.1-43.4). No IgM antibodies were detected in animals tested (0/243; 0.0%; 95%CI: 0.0-1.5) by capture-ELISA. The main risk factors associated with WNV exposure in equids were age (adult and geriatric), breed (crossbred) and the absence of a disinsection programme on the facilities. In wild birds, IgG antibodies against flaviviruses were found in 32.7% (56/171; 95%CI: 26.8-38.6) using bELISA, giving an individual WNV seroprevalence of 19.3% (95%CI: 14.3-24.3) after VNT. Seropositivity was found in 37.8% of the 37 species analysed. Species group (raptors), age (>1-year old) and size (large) were the main risk factors related to WNV seropositivity in wild birds. Our results indicate high exposure and widespread distribution of WNV in equid and wild bird populations in Spain after the epidemic outbreak in 2020. The present study highlights the need to continue and improve active surveillance programmes for the detection of WNV in Spain, particularly in those areas at greatest risk of virus circulation.

Asociación Micobacterias-VIH/SIDA en Pacientes Atendidos en un Hospital Universitario en Bogotá, Colombia

OBJECTIVE

Evaluating the frequency of mycobacterium infection in an HIV-positive population and its influence on medium-term survival, along with clinical and epidemiological factors associated with co-infection.

METHODS

Several clinical specimens were studied for mycobacteria in a sample of 92 HIV+ patients at the San Juan de Dios teaching-hospital in Bogota, Colombia, during 1996. Factors associated with infection were measured using a prevalence ratio (PR), CI=95%, and logistic regression was used in the multivariable models. The likelihood of survival for three months was measured using Kaplan-Meir curves and factors associated with survival were assessed using Rate ratios and Cox's model.

RESULTS

Eight percent of the patients had tuberculosis and 6% of them were found to be infected with atypical mycobacterium. Mycobacterium avium complex (MAC) was the most frequent species, followed by M. fortuitum and M. chelonae. Mixed infections with M. tuberculosis and MAC were diagnosed in one patient and two different species of atypical mycobacterium were isolated in other two cases. Patients suffering from tuberculosis and stages III or IV HIV infection had a 16% survival rate.

CONCLUSIONS

Tuberculosis-HIV/AIDS frequency and atypical Mycobacterium-HIV/AIDS' association were very similar. The most frequently isolated atypical mycobacterium specie in this study was MAC. Survival rate was lower for patients infected by M. tuberculosis and even lower when a multi-resistant strain was involved. The most important clinical factor associated with M. tuberculosis was the presence of fever and loss of weight with mycobacterial infection. Blood provided the best samples for isolating mycobacteria.

Frequency of tuberculous and non-tuberculous mycobacteria in HIV infected patients from Bogota, Colombia

BACKGROUND

The prevalence of infections by Mycobacterium tuberculosis and non-tuberculous Mycobacterium species in the HIV-infected patient population in Colombia was uncertain despite some pilot studies. We determined the frequency of isolation of Mycobacterium tuberculosis and of non-tuberculous Mycobacterium species in diverse body fluids of HIV-infected patients in Bogota, Colombia.

METHODS

Patients who attended the three major HIV/AIDS health care centres in Bogota were prospectively studied over a six month period. A total of 286 patients were enrolled, 20% of them were hospitalized at some point during the study. Sixty four percent (64%) were classified as stage C, 25% as stage B, and 11% as stage A (CDC staging system, 1993). A total of 1,622 clinical samples (mostly paired samples of blood, sputum, stool, and urine) were processed for acid-fast bacilli (AFB) stain and culture.

RESULTS

Overall 43 of 1,622 cultures (2.6%) were positive for mycobacteria. Twenty-two sputum samples were positive. Four patients were diagnosed with M. tuberculosis (1.4%). All isolates of M. tuberculosis were sensitive to common anti-tuberculous drugs. M. avium was isolated in thirteen patients (4.5%), but only in three of them the cultures originated from blood. The other isolates were obtained from stool, urine or sputum samples. In three cases, direct AFB smears of blood were positive. Two patients presented simultaneously with M. tuberculosis and M. avium.

CONCLUSIONS

Non-tuberculous Mycobacterium infections are frequent in HIV infected patients in Bogota. The diagnostic sensitivity for infection with tuberculous and non-tuberculous mycobacteria can be increased when diverse body fluids are processed from each patient.

[Quality of sputum microscopy in the network of tuberculosis bacteriology laboratories in Colombia]

The objective of this study was to evaluate the technical quality of sputum microscopy carried out for diagnostic purposes in the Network of Tuberculosis Bacteriology Laboratories in Colombia. The National Central Reference Laboratory received 6,529 slides for reexamination from the network of 513 sectional, regional, and local laboratories, which contributed 33.2%, 27.6%, and 39.2%, respectively, of the slides. These included all the positive (3,283) and negative (3,246) smears processed during a 4-month period. The reexamination was carried out by six laboratory workers who did not know the origin of the slides or the original diagnosis. When qualitative problems were detected, a second reexamination was done, which significantly increased the percentage of agreement for both the positive results (93.9%) and the negative (98.7%). Overall, the level of agreement was 96.3%. A significant correlation was found (P < 0.05) between good slide preparation and staining and agreement in the readings, as well as between thin smears, presence of fuchsin precipitates, and deficient coloration and conflicting readings (P < 0.05). The highest percentages of agreement were associated with laboratories that performed the largest number of sputum examinations each month (96.5%), and with readings done by experienced, university-trained bacteriologists (96.6%). It is concluded that indirect technical supervision and ongoing training of laboratory personnel are important determinants of the impact of the tuberculosis control program.