The ecology of herd immunity

The COVID-19 pandemic that began in early 2020 is currently the subject of thousands of articles on the various aspects of its epidemiology. One recurrent theme is the phenomenon of herd immunity or herd effect. In this article, I present a short history of the concept, the arguments around its nomenclature, and the ecologist's view of the herd effect, using the case history of the sleeping sickness control in Africa.

Synthetic ligustrazine based cyclohexanone and oxime analogs as Anti-Trypanosoma and Anti-Leishmanial agentes

In the present study a series of 34 synthetic ligustrazine-containing α, ß-Unsaturated carbonyl-based compounds and oximes, recognized as anticancer compounds were assessed against protozoa of the Trypanosoma and Leishmania species. Ligustrazine, chemically known as tetramethylpyrazine (TMP), was selected as the core moiety for the synthesis of α, ß-Unsaturated carbonyl-based compounds and these compounds were selected as precursors for the synthesis of new oximes. Some derivates, including 5f and 6i, showed multiple activities against all tested strains. In particular compounds 5f and 8o are the most potent and they are, therefore, potential candidates for trypanosomiasis and leishmaniasis

"Hipnóticos" na metrópole: africanos no Hospital Colonial de Lisboa nas primeiras décadas do século XX / "Hypnotics" in the metropolis: Africans in the Colonial Hospital of Lisbon during the early twentieth century

Resumo No início do século XX, alguns médicos portugueses foram à África estudar a chamada doença do sono. Entre eles estava Ayres Kopke, membro da primeira missão médica à África Ocidental Portuguesa. De regresso a Lisboa, o professor da Escola de Medicina Tropical continuou suas pesquisas, inclusive por meio da observação de doentes trazidos para a metrópole. Desde 1903, as repartições de saúde nas colônias estavam incumbidas de enviar doentes com determinadas patologias exóticas para o Hospital Colonial de Lisboa. Com base em documentos desse hospital, incluindo fotografias dos doentes, então chamados de hipnóticos, o artigo aborda a importância das experiências com humanos na metrópole para o avanço da medicina tropical durante o colonialismo.

Abstract At the start of the twentieth century, some Portuguese physicians traveled to Africa to study sleeping sickness (African trypanosomiasis). One was Ayres Kopke, a member of the first medical mission to Portuguese West Africa and professor at the School of Tropical Medicine. After returning to Lisbon, Kopke continued his research, which included observation of patients brought to the metropolis. Starting in 1903, health departments in the colonies were responsible for sending patients with certain exotic diseases to the Colonial Hospital of Lisbon. Based on documents from this hospital including photographs of patients (who at that time were called "hypnotics"), this article discusses the importance of human experiments in Lisbon for advances in tropical medicine during the colonial period.

Public health and tropical modernity: the combat against sleeping sickness in Portuguese Guinea, 1945-1974 / Saúde pública e modernidade tropical: o combate à doença do sono na Guiné Portuguesa, 1945-1974

Until the establishment of the “Commission for the study of and combat against sleeping sickness” (Missão de estudo e combate à doença do sono) in 1945, underfunded and understaffed health services had not been a priority for the colonial administration in Portuguese Guinea. The Commission not only implemented endemic disease control in the territory under the auspices of metropolitan institutions, but also provided preventive public healthcare to the local population. Its relative success in reducing the negative impact of Human African Trypanosomiasis turned the colony into an apparent model of tropical modernity. In the process, the local evolution of the disease was marginalized, despite the tacit but contested recognition by some health professionals of the role of popular healthcare.

Os serviços de saúde que sofreram de uma crónica falta de recursos humanos e materiais nunca foram uma prioridade para a administração colonial na Guiné Portuguesa até a criação da Missão de Estudo e Combate à Doença do Sono em 1945. Além de introduzir o controlo de doenças endémicas sob a tutela de instituições metropolitanas, a Missão também providenciou cuidados preventivos de saúde pública para as populações locais. O sucesso relativo da redução do impacto nocivo da tripanossomíase africana parece ter transformado a colónia num modelo de modernidade tropical. Porém, as trajetórias locais da doença foram marginalizadas, apesar do reconhecimento tácito mas contestado por profissionais de saúde do papel de cuidados populares de saúde.

Bactéria ou parasita? a controvérsia sobre a etiologia da doença do sono e a participação portuguesa, 1898-1904 / Bacteria or parasite? the controversy over the etiology of sleeping sickness and the Portuguese participation, 1898-1904

A etiologia da doença do sono era desconhecida até o início do século XX. Essa doença tipicamente africana em breve se tornaria o principal obstáculo à colonização europeia. O envio de missões científicas às colônias para seu estudo in loco tornou-se inevitável. Portugal enviou a primeira missão de estudo, a Angola, em 1901, e a Royal Society of London apoiou duas missões britânicas de estudo da doença, em Entebe. O resultado dessas investigações estabeleceu uma controvérsia, na qual Portugal esteve envolvido de 1898 a 1904, no circuito nacional e internacional, objeto de análise deste artigo.

The etiology of sleeping sickness was unknown until the early twentieth century. This African disease soon became the main obstacle to European colonization. Sending scientific missions to the colonies to monitor its progression in loco thus became inevitable. Portugal sent the first research mission to Angola in 1901, and the Royal Society of London sponsored two British missions to study the disease in Entebbe (1902 and 1903). Their results led to a controversy in which Portugal was involved from 1898 to 1904, on the national and international circuits, analysed in this article.