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About 40 million people travel from abroad to the United States per annum; many international travelers arrive in urban centers, and those who are ill will seek care there. Clinicians working in urban hospitals or near points of international arrival must be familiar with diseases commonly acquired abroad as well as uncommon but potentially serious conditions such as emerging and re-emerging infectious diseases. The assessment of the ill international traveler begins with a thorough history including the patient’s itinerary, activities, and risk factors. A familiarity with conditions endemic to the region of travel, timing of exposure, and knowledge of incubation period will allow the clinician to form a focused differential diagnosis. Knowledge of the specific diseases for which the patient is at risk, their potential complications, and the patient’s clinical status will determine need for diagnostic testing, empiric treatment, and ultimate disposition.
Intermittent fever is a historical diagnosis with a contested meaning. Historians have associated it with both benign malaria and severe epidemics during the Early Modern Era and early nineteenth century. Where other older medical diagnoses perished under changing medical paradigms, intermittent fever ‘survived’ into the twentieth century. This article studies the development in how intermittent fever was framed in Denmark between 1826 and 1886 through terminology, clinical symptoms and aetiology. In the 1820s and 1830s, intermittent fever was a broad disease category, which the diagnosis ‘koldfeber’. Danish physicians were inspired by Hippocratic teachings in the early nineteenth century, and patients were seen as having unique constitutions. For that reason, intermittent fevers presented itself as both benign and severe with a broad spectrum of clinical symptoms. As the Parisian school gradually replaced humoral pathology in the mid-nineteenth century, intermittent fever and koldfeber became synonymous for one disease condition with a nosography that resembles modern malaria. The nosography of intermittent fever remained consistent throughout the second half of the nineteenth century. Although intermittent fever was conceptualized as caused by miasmas throughout most of the nineteenth century, the discovery of the Plasmodium parasite in 1880 led to a change in the conceptualization of what miasmas were. The article concludes that the development of how intermittent fever was framed follows the changing scientific paradigms that shaped Danish medicine in the nineteenth century.
A broad range of parasites were present in ancient Egypt and Nubia, with 15 different species, including ectoparasites, helminths, and protozoa. Some are spread directly from one person to another (such as pinworm and head lice), some pass through animals as part of their life cycle (such as Taenia tapeworms, fish tapeworm, and trichinella), while others require biting insect vectors to spread them (such as malaria, leishmaniasis, and filariasis). Around 40% of ancient Nubians had head lice, 10% of Nubians were infected by visceral leishmaniasis, 22% of Egyptian mummies were positive for malaria, and 17% were positive for schistosomiasis. As malaria and schistosomiasis cause chronic anaemia and fatigue during physical work, they must have been responsible for a considerable drain upon the capabilities of the workforce in these civilizations along the Nile.
Despite major investment in sanitation infrastructure, intestinal parasites spread by faecal contamination of food and water were a particular problem everywhere in the Roman world. Similarly, ectoparasites such as lice and fleas were common despite the Roman enthusiasm for washing in communal bathhouses and the use of delousing combs. However, some parasites seem to be much more regional in their distribution, likely due to climate variations. Fish and Taenia tapeworms, spread by eating raw or undercooked fish, pork, or beef were more common in northern Europe than southern Europe, possibly due to the fact that the hot climate in the south made raw fish and meat go off faster than in the cooler north. In contrast, malaria seems to have been much more common in the Mediterranean region than in northern Europe, as the warm climate of the south created breeding sites for the Anophales mosquito, which transmitted the parasite. Roman period medical texts by Galen and other physicians showed awareness of a number of parasites and tried to explain them in the context of the humoral theory. Treatment involved trying to rebalance the humours in order to return the individual to health.
We have explored some of the ways in which parasites can tell us about past human migrations. Sometimes an expansion to the endemic area of a parasite shows that migration had found an environment receptive to that species’ life cycle. Examples date across evolutionary time, from lice in our hominin ancestors to transatlantic slavery in the last few hundred years. In contrast, in many more examples the parasite failed to become endemic in the new region due to the lack of key elements required for its life cycle. The role of human ectoparasites in the spread of epidemic and pandemic disease has been vitally important throughout human history. As humans move they take their ectoparasites with them, their bodies acting as an incubator for bacterial infectious diseases. While bubonic plague is certainly the best recorded and researched of these epidemics, many others such as epidemic typhus and trench fever would have caused disease and death in past societies. Although human fleas and lice in themselves have only limited impact upon health, it seems likely that far more of our ancestors have died from diseases spread by their ectoparasites than ever died from intestinal parasites.
The generation of transgenic plants and animals is discussed in Chapter 16. The technology is now well established, but remains a controversial area in terms of public perception and acceptance. Scientific, regulatory, ethical, political and commercial factors together present a complex framework within which the development of transgenic plants and animals is placed. As well as considering the technical procedures used to generate transgenics, these broader aspects (and their impact on the success or failure of a transgenic product) are considered. The development of Golden Rice, and the subsequent political issues around its deployment, illustrate the complexity of the topic. Paradoxically, transgenic animals often generate less negative reaction from the anti-GMO (genetically modified organism) movement than transgenic plants, with most concerns being around animal welfare issues. This is particularly true where the product is, for example, a demonstrably positive therapeutic; when transgenic animals are generated for consumption, the GMO debate tends to become polarised to the same extent as transgenic crops.
Chapter 6 investigates the WHO’s malaria and tuberculosis control programs in the 1950s and 1960s, which made use of statistical collection and analysis. Numbers had become omnipresent in program design and implementation by this time, and experts at the WHO and in the Taiwanese government used their public health knowledge to justify their selection of statistics. WHO experts and Taiwanese health officers also used numbers to advocate for their programs. In particular, experts curated numbers to bolster their arguments in the context of ongoing policy debates at the WHO. Their ways of curating numbers were different as they occupied different positions within global health policy-making. Experts within the WHO mobilized their knowledge on the diseases in question to justify their selection of certain statistics over others, while their Taiwanese colleagues used numbers to present Taiwan as a viable testing ground for WHO policies, with a view to obtaining financial and technical support.
Long-haul tourists visiting South Africa are always fascinated by the clicks of isiXhosa. Foreign to their ears, the eighteen click consonants can be grouped into three types: the ‘c’ is a dental click made by the tongue at the back of the mouth, the lateral ‘x’ is made by the tongue at the sides of the mouth, and the alveolar ‘q’ is made by the tip of the tongue on the roof of the mouth.
IsiXhosa is part of the Nguni language group, which also includes Zulu and southern and northern Ndebele. Yet few of these or the other South African vernacular languages have clicks, and those that do have them use them far less. How is it that isiXhosa came to use clicks so commonly?
One clue comes from the other languages of southern Africa that also make use of clicks – and there are lots of them.
Natural disasters (NDs) are calamitous phenomena that can increase the risk of infections in disaster-affected regions. This study aimed to evaluate the frequency of malaria and cutaneous leishmaniasis (CL) before and after earthquakes, floods, and droughts during the past four decades in Iran.
Malaria and CL data were obtained from the reports of the Ministry of Health and Medical Education in Iran for the years 1983 through 2017. The data of NDs were extracted from the Centre for Research on the Epidemiology of Disasters (CRED). Interrupted time series analysis with linear regression modeling was used to estimate time trends of mentioned diseases in pre- and post-disaster conditions.
For the periods preceding the disasters drought and flood, a decreasing time trend for malaria and CL was found over time. The time trend of malaria rate preceding the 1990 earthquake was stable, a downward trend was found after 1990 disaster until 1997 (β coefficient: −10.7; P = .001), and this declining trend was continued after 1997 disaster (β coefficient: −2.7; P = .001). The time trend of CL rate preceding the 1990 earthquake had a declining trend, an upward trend was found after 1990 earthquake until 1999 (β coefficient: +8.7; P = .293), and a slight upward trend had also appeared after 1999 earthquake (β coefficient: +0.75; P = .839).
The results of the current study indicated the occurrence of earthquakes, floods, and droughts has no significant effect on the frequency of malaria and CL in Iran.
Increases in bed net coverage and antimalarial treatment have reduced the risk of malaria in sub-Saharan Africa. However, the pace of reduction has slowed, and new tools are needed to reverse this trend. We evaluated houses screened with insecticide-treated ceiling nets using a cluster randomized-controlled trial in western Kenya. The primary endpoints were Plasmodium falciparum PCR-positive prevalence (PCRPfPR) of children from 7 months to 10 years old and anopheline density. Ceiling nets and bed nets were provided to 1073 houses, and 1162 houses were provided with bed nets only. The treatment and control arms each had four clusters. We conducted three epidemiological and entomological post-intervention surveys over the course of a year and a half. Each epidemiological survey targeted 150 children per cluster, and entomological surveys targeted 25 houses. When the three surveys were combined, the median PCRPfPRs were 23% (IQR 8%) in the intervention arm and 42% (IQR 12%) in the control arm. The adjusted risk ratio (RR) was 0.53 [95% confidence interval (CI) 0.41–0.71; P = 0.029]. The median anopheline densities were 0.4 (IQR 0.4) and 2.0 (IQR 1.4), respectively. The adjusted RR was 0.41 (95% CI 0.29–0.90; P = 0.029). The present study indicates additional protection from insecticide-screened ceilings over the current best practice.
The article de-centres the global history of disease by examining the agency of Eastern European expertise at international organizations and during decolonization. It challenges accounts of anti-malaria policies at the League of Nations Health Organization and at the World Health Organization written from a Western, particularly North American perspective, or on the basis of local reactions to Western interventions. The contribution proposes an analysis of circulations and ideas across multiple cultural, social and political spaces: post-imperial European states, (post)colonial territories and bureaucracies of international organizations. From the 1920s to the 1960s, Eastern European experts played a crucial role in the transformation of malaria from an imperial disease that tested governance over ‘tropical’ peoples into an issue of global health and nation-state building. However, regional representatives reproduced civilizational hierarchies intrinsic to North–South biomedical relations. The global entanglements of Eastern European malariology show that liberation from disease was less about communism or liberalism, and more about national renewal, statehood and world hierarchies.
Inflammation and infections such as malaria affect estimates of micronutrient status. Medline, Embase, Web of Science, Scopus and the Cochrane library were searched to identify studies reporting mean concentrations of ferritin, hepcidin, retinol or retinol binding protein in individuals with asymptomatic or clinical malaria and healthy controls. Study quality was assessed using the US National Institute of Health tool. Random effects meta-analyses were used to generate summary mean differences. In total, forty-four studies were included. Mean ferritin concentrations were elevated by: 28·2 µg/l (95 % CI 15·6, 40·9) in children with asymptomatic malaria; 28·5 µg/l (95 % CI 8·1, 48·8) in adults with asymptomatic malaria; and 366 µg/l (95 % CI 162, 570) in children with clinical malaria compared with individuals without malaria infection. Mean hepcidin concentrations were elevated by 1·52 nmol/l (95 % CI 0·92, 2·11) in children with asymptomatic malaria. Mean retinol concentrations were reduced by: 0·11 µmol/l (95 % CI −0·22, −0·01) in children with asymptomatic malaria; 0·43 µmol/l (95 % CI −0·71, −0·16) in children with clinical malaria and 0·73 µmol/l (95 % CI −1·11, −0·36) in adults with clinical malaria. Most of these results were stable in sensitivity analyses. In children with clinical malaria and pregnant women, difference in ferritin concentrations were greater in areas with higher transmission intensity. We conclude that biomarkers of iron and vitamin A status should be statistically adjusted for malaria and the severity of infection. Several studies analysing asymptomatic infections reported elevated ferritin concentrations without noticeable elevation of inflammation markers, indicating a need to adjust for malaria status in addition to inflammation adjustments.
Infection by malaria parasites (Plasmodium spp.) remains one of the leading causes of morbidity and mortality, especially in tropical regions of the world. Despite the availability of malaria control tools such as integrated vector management and effective therapeutics, these measures have been continuously undermined by the emergence of vector resistance to insecticides or parasite resistance to frontline antimalarial drugs. Whilst the recent pilot implementation of the RTS,S malaria vaccine is indeed a remarkable feat, highly effective vaccines against malaria remain elusive. The barriers to effective vaccines result from the complexity of both the malaria parasite lifecycle and the parasite as an organism itself with consequent major gaps in our understanding of their biology. Historically and due to the practical and ethical difficulties of working with human malaria infections, research into malaria parasite biology has been extensively facilitated by animal models. Animals have been used to study disease pathogenesis, host immune responses and their (dys)regulation and further disease processes such as transmission. Moreover, animal models remain at the forefront of pre-clinical evaluations of antimalarial drugs (drug efficacy, mode of action, mode of resistance) and vaccines. In this review, we discuss commonly used animal models of malaria, the parasite species used and their advantages and limitations which hinder their extrapolation to actual human disease. We also place into this context the most recent developments such as organoid technologies and humanized mice.
The association between the ABO blood group and the risk of malaria during pregnancy has not been clearly established. The present study summarised relevant knowledge and reassessed the association through meta-analysis. Articles in MEDICINE and PubMed published before 30 November 2021 were searched. Five studies satisfied the inclusion criteria and were enrolled in the meta-analysis. It was shown that primiparae with different ABO blood group, multiparae with blood group A and non-A, AB and non-AB had a comparable risk of malaria. However, multiparae with blood group B had a significantly higher risk than non-B group [odds ratio (OR) = 1.23, 95% confidence interval (CI) was 1.01 to 1.50, P = 0.04], while multiparae with blood group O had a significantly lower risk than non-O group (OR = 0.78, 95% CI was 0.63 to 0.97, P = 0.03). Therefore, the ABO blood group may not result in a different risk of malaria in primiparae. Blood group B is potentially a risk factor while blood group O is a protective factor for multiparae.
From nearly any perspective and metric, the effects of malaria on the African continent have been persistent and deep. By focusing on the malady of malaria and the last century of biomedical interventions, Graboyes and Alidina raise critical historical, ethical, and scientific questions related to truth telling, African autonomy, and the obligations of foreign researchers. They provide a condensed history of malaria activities on the continent over the past 120 years, highlighting the overall history of failures to eliminate or control the disease. A case study of the risks of rebound malaria illustrates the practical and moral problems that abound when historical knowledge is ignored. In light of current calls for renewed global eradication efforts, Graboyes and Alidina provide evidence for why historical knowledge must be better integrated into global health epistemic realms.
1. Malaria is caused by a protozoan parasite of the Plasmodium genus, transmitted by mosquitoes.
2. There are five species of Plasmodium that regularly infect humans; Plasmodium falciparum is responsible for the vast majority of malarial deaths.
3. Severe malaria is a medical emergency, with mortality from untreated disease (particularly cerebral malaria) approaching 100 per cent. Early diagnosis and prompt, effective treatment are essential.
4. Parenteral artesunate is the treatment of choice for all severe malaria.
5. It is important to remember there are many causes of critical illness in the returning traveller, with a wide number of differentials, including, but not limited to: enteric fever (typhoid and paratyphoid), hepatitis, dengue or other arboviruses, avian influenza and viral haemorrhagic fever.
Plasmodium coatneyi has been proposed as an animal model for human Plasmodium falciparum malaria as it appears to replicate many aspects of pathogenesis and clinical symptomology. As part of the ongoing evaluation of the rhesus macaque model of severe malaria, a detailed ultrastructural analysis of the interaction between the parasite and both the host erythrocytes and the microvasculature was undertaken. Tissue (brain, heart and kidney) from splenectomized rhesus macaques and blood from spleen-intact animals infected with P. coatneyi were examined by electron microscopy. In all three tissues, similar interactions (sequestration) between infected red blood cells (iRBC) and blood vessels were observed with evidence of rosette and auto-agglutinate formation. The iRBCs possessed caveolae similar to P. vivax and knob-like structures similar to P. falciparum. However, the knobs often appeared incompletely formed in the splenectomized animals in contrast to the intact knobs exhibited by spleen intact animals. Plasmodium coatneyi infection in the monkey replicates many of the ultrastructural features particularly associated with P. falciparum in humans and as such supports its use as a suitable animal model. However, the possible effect on host–parasite interactions and the pathogenesis of disease due to the use of splenectomized animals needs to be taken into consideration.
This research aims to determine whether the combination of epidemiological and clinical features can predict malaria. Diagnostic investigation detected 22.3% of individuals with Plasmodium vivax (P. vivax) malaria, with significant predominance of the male gender. The malaria triad (fever, chills and headache) had a more expressive frequency (81.1%) in individuals with positive thick blood than those with negative thick blood smear (65.1%), although there was no statistical significance. Among the variables analysed as predictive for positive thick blood smear, it was observed that personal history of travel to an endemic malaria area and past malaria infection (PMI) were significantly associated with malaria, even in multiple logistic regression. Fever had the higher sensitivity (94.6%) and past malaria history had the greater specificity (68.2%), with accuracy of 23.5% and 67.5%, respectively. In combined analysis, fever with chills had the highest sensitivity (91.9%), but low accuracy (38.5%). High specificity (91.5%) was found in the association of malaria triad, PMI and history of travel to endemic malaria area (which along with anorexia, was higher 94.6%), with good accuracy (80.7%), suggesting that the screening of patients for performing thick blood smear can be based on these data. The epidemiological features and the malaria triad (fever, chills and headache) can be predictors for identification of malaria patients, concurring to precocious diagnosis and immediate treatment of individuals with malaria.
All the more telling for being an arbitrary and often intimate historical record, poetry provides the primary source for this chapter’s account of nineteenth-century medicine. Poems by John Gibson, Thomas Fessenden, George Crabbe, William Wordsworth, and Humphrey Davy disclose that the practice of medicine, whether by quacks or the learned, was so ineffectual at the start of the century as to allow the Romantics to plausibly argue for the curative effects of poetry and the imagination, both of which became integral to a new science of life. The professional medicine that sprang from this science, however, asserted its autonomy from poetry, most effectively by pathologising such poets as John Keats and Oscar Wilde, who in turn offered their own verse ripostes. Its positivism and ‘hands-on’ diagnostics yielded new conceptions of the body and touch that Alfred Tennyson, G. M. Hopkins, and Walt Whitman each reflect upon in their poetry. Finally, the growing acceptance of the germ theory of disease enabled pathologies of art as illness that are variously elaborated upon and joked about by Edward Lear, Henry Savile Clerk, Wilde, and Ronald Ross, who also reaches for poetry to record his sublimely momentous discovery of the malaria pathogen in 1896.