A serological survey of canine leptospirosis in the city of Belgrade, Serbia

Canine leptospirosis is a zoonosis caused by bacteria belonging to the genus Leptospira. Dogs are one of the animal species involved in the cycle of preservation and transmission of leptospirosis in urban areas. Serological testing for the presence of specific antibodies against Leptospira spp. in dogs was continuously performed between 2010 and 2020 in the city of Belgrade. At the request of the owners themselves, other veterinary laboratories or laboratory clinics, 179 blood sera from 179 dogs were examined in the Laboratory for Immunology, Scientific Institute of Veterinary Medicine of Serbia. Blood sera samples from dogs were examined using the standard microscopic agglutination test (MAT) for the presence of specific antibodies against seven different serovars of Leptospira: Pomona, Icterohaemorrhagiae, Grippotyphosa, Sejroe, Canicola, Bataviae, and Australis. The number of seropositive dogs was 17/179 (9.5%). Among all examined sera, the highest titre of seropositive samples was to serovar Icterohaemorrhagiae (10/17, 58.8%), followed by Pomona (4/17, 23.5%), and serovar Canicola (3/17, 17.6%). Specific antibodies for serovars Grippotyphosa, Sejroe, Bataviae and Australis were not detected in any of the dog sera. Cross-reaction (the presence of two or three titres with different values where one of them was higher than others) between different serovars was diagnosed in a low number of sera (n=4), with the following serovars: Icterohaemorrhagiae and Pomona (n=3) and Pomona and Canicola (n=1). The confirmed specific antibody titres for Leptospira spp. were between 1:100 to 1:3000 (5 sera had titres of 1:100, 7 had titres of 1:300, 4 had titres of 1:1000, and 1 serum had a titre 1:3000). Monitoring canine leptospirosis is a useful tool in preventing leptospirosis in Belgrade.

Seroprevalence of Toxoplasma gondii in Pinnipeds under Human Care and in Wild Pinnipeds

Toxoplasma gondii infection has been reported in numerous species of marine mammals, some of them with fatal consequences. A serosurvey for T. gondii infection was conducted in pinnipeds from an oceanographic park in Portugal (n = 60); stranded pinnipeds on the Portuguese coast (n = 10); and pinnipeds captured in Lorenzensplate, Germany (n = 99). Sera from 169 pinnipeds were tested for the presence of antibodies to T. gondii by the modified agglutination test with a cut-off titre of 25. An overall seroprevalence of 8.9% (95% confidence interval: 5.1–14.2) was observed. Antibody titres of 25, 50, 100, 1600 and ≥3200 were found in five (33.3%), two (13.3%), five (33.3%), one (6.7%) and two (13.3%) animals, respectively. Pinnipeds under human care had a seroprevalence of 20.0% (12/60), in contrast to 2.8% (3/109) in wild pinnipeds (p < 0.001). General results suggest a low exposure of wild pinnipeds to T. gondii, while the seroprevalence found in pinnipeds under human care highlights the importance of carrying out further studies. This is the first serological survey of T. gondii in pinnipeds in Portugal and the first infection report in South African fur seal (Arctocephalus pusillus pusillus).

Sero Prevalence of COVID-19 in Palestine in 2020

COVID-19 affected different countries differently. The WHO/ PNIPH, WHO/EMRO, and the Palestinian MoH, with assistance from the PCBS carried out a serological survey in the occupied Palestinian Territories in order to estimate the actual number of COVID-19 infection by the end of December 2020. A sample stratified by Region, district, and by type (urban, rural, and refugee camp), and accounting for gender, was taken from Gaza and the West Bank. The results show that 39% of the oPt (38% of the West Bank and 40% of Gaza), had been infected with COVID-19 by the end of December, almost 10 times the number that was detected by targeted Rt-PCR testing.

Seroprevalence and Infection Attack Rate of COVID-19 in Indian Cities

Objectives. Serological surveys were used to infer the infection attack rate in different populations. The sensitivity of the testing assay, Abbott, drops fast over time since infection which make the serological data difficult to interpret. In this work, we aim to solve this issue. Methods. We collect longitudinal serological data of Abbott to construct a sensitive decay function. We use the reported COVID-10 deaths to infer the infections, and use the decay function to simulate the seroprevalence and match to the reported seroprevalence in 12 Indian cities. Results. Our model simulated seroprevalence match the reported seroprevalence in most (but not all) of the 12 Indian cities we considered. We obtain reasonable infection attack rate and infection fatality rate for most of the 12 Indian cities. Conclusions. Using both reported COVID-19 deaths data and serological survey data, we infer the infection attack rate and infection fatality rate with increased confidence.