The future of sperm: a biovariability framework for understanding global sperm count trends

The past 50 years have seen heated debate in the reproductive sciences about global trends in human sperm count. In 2017, Levine and colleagues published the largest and most methodologically rigorous meta-regression analysis to date and reported that average total sperm concentration among men from 'Western' countries has decreased by 59.3% since 1973, with no sign of halting. These results reverberated in the scientific community and in public discussions about men and masculinity in the modern world, in part because of scientists' public-facing claims about the societal implications of the decline of male fertility. We find that existing research follows a set of implicit and explicit assumptions about how to measure and interpret sperm counts, which collectively form what we term the Sperm Count Decline hypothesis (SCD). Using the study by Levine and colleagues, we identify weaknesses and inconsistencies in the SCD, and propose an alternative framework to guide research on sperm count trends: the Sperm Count Biovariability hypothesis (SCB). SCB asserts that sperm count varies within a wide range, much of which can be considered non-pathological and species-typical. Knowledge about the relationship between individual and population sperm count and life-historical and ecological factors is critical to interpreting trends in average sperm counts and their relationships to health and fertility.

Septicemia decorrente de pododermatites em canários de cor (Serinus canarius)

Relataram-se um surto de pododermatite e quadro septicêmico em aves de um canaril comercial. Quarenta e quatro canários de cor foram escolhidos de forma aleatória, sem distinção de sexo, idade ou cor, os quais vieram a óbito naturalmente, após terem sido afetados pela pododermatite, sem que tivessem se submetido a tratamento prévio. As aves mortas foram encaminhadas para o exame necroscópico, onde amostras de tecidos das áreas afetadas foram colhidas para exames microbiológico, micológico e histológico. Todas as aves necropsiadas apresentavam pododermatite, com inflamação em um ou mais dedos, de aspecto nodular, com ou sem presença de úlceras ou necrose. Staphylococcus aureus plasma coagulase positivo foi isolado dos pés e do fígado de todas as aves. Foi observado que todas as linhagens isoladas foram resistentes aos antimicrobianos da classe das penicilinas (penicilina G e ampicilina) e parcialmente sensíveis ou resistentes à ciprofloxacina. Apenas metade dos isolados foram sensíveis à neomicina e à estreptomicina. Problemas de saúde pública podem estar relacionados ao surgimento de animais reservatórios de cepas multirresistentes para seres humanos contactantes, como neste caso.

Surveillance for rotavirus in Argentina

Group A rotaviruses are the major cause of severe gastroenteritis in young children worldwide. Because rotavirus vaccination appeared imminent, a nationwide surveillance program was organized between October 1996 and October 1998 in the largest Argentine cities. Surveillance for disease burden, rotavirus detection, and rotavirus typing was undertaken at nine locations. Results showed rotavirus to be associated with 42% of diarrhea admissions. Although the prevalent G types changed from year to year, common G types were found in 96% of the cases and were usually associated with common P types. Uncommon G types, G9 and G5, were found at low prevalence and uncommon G/P combinations occurred at almost every study site. These data suggest that a rotavirus vaccine could substantially decrease the rotavirus disease burden in Argentina, but that introduction of a vaccine should be accompanied by a concurrent surveillance system.

[Rotavirus laboratory network: results after one year of observation]

Rotavirus is the most common cause of severe diarrhea in children and it has been estimated that in Argentina Rotavirus is responsible for 21,000 hospitalizations, 85,000 medical attentions and an annual medical cost of US$ 27 millions. Given that a Rotavirus vaccine is about to be approved, a laboratory network based surveillance system was organized. Herein, we present the results after one year of study. Severe diarrhea was responsible for 9% of pediatric hospitalizations and rotavirus was detected in 42.1% of the diarrhea cases. We estimated that Rotavirus causes 3.8% of pediatric hospitalizations. The number of diarrhea and Rotavirus diarrhea hospitalizations was greater during the first year of life (62% and 71.3%, respectively). The number of diarrhea hospitalizations during the December-May semester was significantly higher than the rest of the year. A Rotavirus diarrhea peak was detected between April and June. These results indicate that Rotavirus is the most important etiological agent of severe diarrhea in Argentine children and show the importance of performing Rotavirus diagnosis in every pediatric hospital. The additional costs will be compensated by many benefits such as better use of antibiotics, improved nosocomial spread control, better handling of hospital beds and of laboratory resources and of the hospitalized patient.

Anticipating rotavirus vaccines: review of epidemiologic studies of rotavirus diarrhea in Argentina

Rotavirus is the most common cause of severe diarrhea in children worldwide, and vaccines currently being field-tested could be available for childhood immunization in several years. To assess the rotavirus disease burden in Argentina and the value of future national surveillance for the disease, we reviewed available data on rotavirus detections reported by published and unpublished studies conducted in nine Argentine cities and by a multicenter study. Data from these studies indicated that rotavirus was detected in 20% of 5,226 specimens (within a range of 6% to 54% for different studies) from children hospitalized for diarrhea and in 9% of 6,587 specimens (within a range of 5% to 22% for different studies) from children who were outpatients, members of mixed populations (hospitalized patients and outpatients), or survey subjects in community-based studies. The hospital data showed that while rotavirus was detected throughout the year, a peak occurred during the winter months (May-July) when up to half of the children with diarrhea were found positive for rotavirus. Attempted serotyping of 294 rotavirus-positive specimens for G-protein by three laboratories was successful in 230 cases (78%); the resulting data indicated that serotype G1 was the most common (being present in 60% of the successfully serotyped specimens), followed by G2 (in 20%), G4 (in 14%), and G3 (in 5%). Based on national data for Argentina, we estimate that in 1991 there were roughly 84,500 rotavirus-associated outpatient visits (1 for every 8 births) and 21,000 hospitalizations averaging 4 days in length (1 for every 31 births), all of which entailed direct medical costs estimated at US$ 27.7 million. These preliminary data show that the rotavirus disease burden in Argentine children is extensive and could be decreased by a safe and effective vaccine. Further surveillance is needed to improve our understanding of the epidemiology and distribution of rotavirus strains in Argentina, to more accurately assess the cost-effectiveness of a rotavirus vaccine program, and to indicate what methods might best be used to monitor such a program's impact.