Keeping goblet cells unstressed: new insights into a general principle

Two new studies reveal how the unfolded protein response is regulated in mucin-secreting gut epithelial cells.

Recruitment of trimeric eIF2 by phosphatase non-catalytic subunit PPP1R15B

Regulated protein phosphorylation controls most cellular processes. The protein phosphatase PP1 is the catalytic subunit of many holoenzymes that dephosphorylate serine/threonine residues. How these enzymes recruit their substrates is largely unknown. Here, we integrated diverse approaches to elucidate how the PP1 non-catalytic subunit PPP1R15B (R15B) captures its full trimeric eIF2 substrate. We found that the substrate-recruitment module of R15B is largely disordered with three short helical elements, H1, H2, and H3. H1 and H2 form a clamp that grasps the substrate in a region remote from the phosphorylated residue. A homozygous N423D variant, adjacent to H1, reducing substrate binding and dephosphorylation was discovered in a rare syndrome with microcephaly, developmental delay, and intellectual disability. These findings explain how R15B captures its 125 kDa substrate by binding the far end of the complex relative to the phosphosite to present it for dephosphorylation by PP1, a paradigm of broad relevance.

Descriptive and comparative analysis of mucocutaneous manifestations in patients with dengue fever: A prospective study

BACKGROUND

Dengue is an arbovirosis affecting nearly 4 billion people worldwide. Since 2018, dengue has been re-emerging in Reunion Island. The incidence of mucocutaneous manifestations varies according to the studies and is generally called 'rash'.

OBJECTIVES

To assess the prevalence of different mucocutaneous symptoms and describe the characteristics of patients developing these symptoms and the clinical signs associated with severe dengue.

METHODS

A prospective study was conducted in 2019 at the University Hospital of La Réunion, in patients presenting a positive PCR for dengue. Descriptive analyses were performed. All cases in the prospective study were examined by a dermatologist.

RESULTS

A total of 163 cases were included. The prevalence of mucocutaneous signs was 80.4%. A pruritus was reported in 33.7% cases, an erythematous rash in 29.4% and a mouth involvement including lip, tongue, cheek, angular cheilitis, pharyngitis, mouth ulcer and gingivitis in 31.3%. Most of symptoms appeared in the first days, but some of them could disappear only after the 3rd week. Mucocutaneous signs were not associated with a severe dengue fever (p = 0.54), but ecchymotic purpura was (p = 0.037). In multivariate analysis, skin involvement was associated with flu-like syndrome (headache, pharyngitis, rachis pain) and patient required rehydration but not invasive reanimation.

CONCLUSION

This work confirms the high prevalence of skin symptoms in dengue disease, but also their wide diversity. The mucocutaneous involvement of dengue fever appears to be accompanied by a pronounced flu-like syndrome in people without severity, but careful examination to identify ecchymotic purpura or sign of dehydration in the mucous membranes would better identify cases that may worsen.

Activation of the integrated stress response by inhibitors of its kinases

Phosphorylation of the translation initiation factor eIF2α to initiate the integrated stress response (ISR) is a vital signalling event. Protein kinases activating the ISR, including PERK and GCN2, have attracted considerable attention for drug development. Here we find that the widely used ATP-competitive inhibitors of PERK, GSK2656157, GSK2606414 and AMG44, inhibit PERK in the nanomolar range, but surprisingly activate the ISR via GCN2 at micromolar concentrations. Similarly, a PKR inhibitor, C16, also activates GCN2. Conversely, GCN2 inhibitor A92 silences its target but induces the ISR via PERK. These findings are pivotal for understanding ISR biology and its therapeutic manipulations because most preclinical studies used these inhibitors at micromolar concentrations. Reconstitution of ISR activation with recombinant proteins demonstrates that PERK and PKR inhibitors directly activate dimeric GCN2, following a Gaussian activation-inhibition curve, with activation driven by allosterically increasing GCN2 affinity for ATP. The tyrosine kinase inhibitors Neratinib and Dovitinib also activate GCN2 by increasing affinity of GCN2 for ATP. Thus, the mechanism uncovered here might be broadly relevant to ATP-competitive inhibitors and perhaps to other kinases.

Evaluation of a school-based sun safety education program in Reunion Island, 2016-2017

BACKGROUND

Sun exposure, especially during childhood, is the main environmental risk factor for skin cancers. This study evaluated the impact of the school-based sun safety education program "Living with the Sun" on the knowledge and behavior of primary school children regarding sun safety in Reunion Island.

METHODS

This multicenter, comparative intervention study was conducted in selected primary schools of Reunion during the 2016-2017 school year. The intervention consisted of an in-class slide-show presentation on sun safety, a teaching guide, and school trips during which children were offered sunscreen and were requested to wear sunglasses, a T-shirt, and a cap. The children completed a questionnaire before and after the intervention. The percentage of children wearing a cap in school playgrounds at the end of the school year was compared between paired intervention and control schools.

RESULTS

Seven hundred children from 7 Reunionese schools completed the questionnaire before and after the intervention. There was a statistically significant improvement in children's knowledge of sun safety, with differences between schools, teachers, school levels, and questionnaire responses. The percentage of children wearing a cap at the end of the school year was significantly higher in intervention schools compared to control schools.

CONCLUSIONS

Children's knowledge and behavior regarding sun safety improved significantly as a result of the intervention.

Hydration and clinical warning signs of Dengue fever in primary care: an observational prospective study

OBJECTIVES

Dengue fever is an arbovirosis expanding worldwide, for which hydration has been reported to reduce the risk of hospitalization. Our objective was to estimate the volume of hydration in Reunionese patients with dengue.

METHODS

A prospective observational study included patients presenting with a 'dengue-like' syndrome in ambulatory care. General practitioners recruited patients during consultation, and beverage consumption over the previous 24 hours was reported at two different times. Warning signs were defined according to the 2009 WHO guidelines.

RESULTS

GPs included 174 patients from April to July 2019. Average oral hydration volume was 1863 mL and 1944 mL, at the 1^st and 2^nd medical consultations, respectively. Water was the most wide consumed liquid. Drinking at least 5 glasses of liquid was significantly associated with fewer clinical warning signs at the 1^st medical consultation (p = 0.044).

CONCLUSIONS

Sufficient hydration volume could prevent dengue warning signs. Further studies with standardized measurement of hydration would be needed.

Impact d'une campagne de vaccination COVID-19 en population carcérale

Introduction

La population carcérale est précaire et peu médicalisée. Les maisons d'arrêt souffrent régulièrement de surpopulation, et ont un flux régulier important d'entrants et de sortants. Le niveau de connaissances médicales est faible et les détenus sont souvent peu ou mal informés quant à la vaccination contre la COVID-19. Nous avons mis en place dans une maison d'arrêt, pouvant accueillir théoriquement 115 détenus, une proposition de vaccination des détenus, par un vaccin ARN messager à partir de juillet 2021. Tous les détenus sont dépistés à l'entrée dans l'établissement. Une épidémie est survenue dans cette même maison d'arrêt fin janvier 2022.

Matériels et méthodes

Nous avons recensé le nombre de patients vaccinés du 1^er juillet 2021 au 31 janvier 2022 et le nombre de doses reçues. Nous avons recensé les détenus positifs lors de l'épidémie et évalué leur statut vaccinal.

Résultats

La maison d'arrêt a enregistré 484 entrées avec des durées de séjours variables. Parmi eux, 115 détenus ont été vaccinés et un total de 195 doses ont été administrées. Nous avons réalisé 96 premières injections, 82 deuxièmes injections et 17 troisièmes injections. Nous avons recensé 16 tests positifs parmi les détenus au 31 janvier 2022, dont 10 (62,5 %) à partir du 26 janvier. Parmi eux, 4 avaient été vaccinés (25 %). Deux patients étaient éligibles à leur troisième dose, un patient avait eu 2 doses récentes et un patient n'avait eu qu'une seule dose. Aucune forme symptomatique n'a justifié une hospitalisation.

Conclusion

La vaccination est un enjeu de santé publique majeur en milieu carcéral, notamment vis-à-vis du SARS-CoV2. La promiscuité et la surpopulation favorisent la circulation de celui-ci, favorisant l'émergence d'épidémies chez une population dont l'état de santé reste fragile.

Aucun lien d'intérêt

Cellular responses to halofuginone reveal a vulnerability of the GCN2 branch of the integrated stress response

Halofuginone (HF) is a phase 2 clinical compound that inhibits the glutamyl-prolyl-tRNA synthetase (EPRS) thereby inducing the integrated stress response (ISR). Here, we report that halofuginone indeed triggers the predicted canonical ISR adaptations, consisting of attenuation of protein synthesis and gene expression reprogramming. However, the former is surprisingly atypical and occurs to a similar magnitude in wild-type cells, cells lacking GCN2 and those incapable of phosphorylating eIF2α. Proline supplementation rescues the observed HF-induced changes indicating that they result from inhibition of EPRS. The failure of the GCN2-to-eIF2α pathway to elicit a measurable protective attenuation of translation initiation allows translation elongation defects to prevail upon HF treatment. Exploiting this vulnerability of the ISR, we show that cancer cells with increased proline dependency are more sensitive to halofuginone. This work reveals that the consequences of EPRS inhibition are more complex than anticipated and provides novel insights into ISR signaling, as well as a molecular framework to guide the targeted development of halofuginone as a therapeutic.

Différencier la COVID-19 et la dengue des autres maladies fébriles dans un contexte de co-épidémie : développement et validation internes des scores COVIDENGUE

Introduction

Matériels et méthodes

Résultats

Conclusion

An Overview of Methods for Detecting eIF2α Phosphorylation and the Integrated Stress Response

Phosphorylation of the translation initiation factor eIF2α is an adaptive signaling event that is essential for cell and organismal survival from yeast to humans. It is central to the integrated stress response (ISR) that maintains cellular homeostasis in the face of threats ranging from viral infection, amino acid, oxygen, and heme deprivation to the accumulation of misfolded proteins in the endoplasmic reticulum. Phosphorylation of eIF2α has broad physiological, pathological, and therapeutic relevance. However, despite more than two decades of research and growing pharmacological interest, phosphorylation of eIF2α remains difficult to detect and quantify, because of its transient nature and because substoichiometric amounts of this modification are sufficient to profoundly reshape cellular physiology. This review aims to provide a roadmap for facilitating a robust evaluation of eIF2α phosphorylation and its downstream consequences in cells and organisms.

Prevalence and risk factors for gonococcal infection in Reunion Island

OBJECTIVE

To determine the prevalence and risk factors for gonococcal infection, and the resistance profile of Neisseria gonorrhoeae (NG) in Reunion Island.

PATIENTS AND METHODS

All patients who visited the four sexually transmitted infection (STI) clinics of Reunion Island between January 2017 and December 2018 were screened by multiplex polymerase chain reaction. Data on patient characteristics were collected using a self-administered questionnaire (reason for screening, marital status, risk-taking behaviors, place of birth, employment status, type of health care coverage, sexual orientation, number of sexual partners, occurrence of extra-marital relationships, history of STIs, and symptomatology. Precarity was defined as being unemployed and/or receiving universal health insurance).

RESULTS

The prevalence of NG (n=4289) in the screened population was 2.8% (95% CI [2.3-3.3]). Minors were especially at-risk (4.4% (95% CI [2.6-7])) and especially girls (5.6% (95% CI [3.2-8.9])). The prevalence observed in the homosexual population was 4.0% [2.6-5.9]. Gonococcal infection was asymptomatic in 56 (69%) patients. For all infection sites, the main risk factors were male minors (P=0.019), individuals living in conditions of precarity (P=0.023), individuals co-infected with chlamydia (P<0.001) or syphilis (P<0.001), and individuals of foreign origin (P=0.006). No NG strain was resistant to ceftriaxone. Strains were resistant to penicillin G, ciprofloxacin, and azithromycin in 22% (20/91), 38% (35/91), and 1% (1/91) of cases, respectively.

CONCLUSION

The prevalence of NG in patients visiting STI clinics in Reunion Island is particularly high among minors. Prevention programs targeting this population should be reinforced and screening should be facilitated in school settings.

Substrate recognition determinants of human eIF2α phosphatases

Phosphorylation of the translation initiation factor eIF2α is a rapid and vital cellular defence against many forms of stress. In mammals, the levels of eIF2α phosphorylation are set through the antagonistic action of four protein kinases and two heterodimeric protein phosphatases. The phosphatases are composed of the catalytic subunit PP1 and one of two related non-catalytic subunits, PPP1R15A or PPP1R15B (R15A or R15B). Here, we generated a series of R15 truncation mutants and tested their properties in mammalian cells. We show that substrate recruitment is encoded by an evolutionary conserved region in R15s, R15A325-554 and R15B340-639. G-actin, which has been proposed to confer selectivity to R15 phosphatases, does not bind these regions, indicating that it is not required for substrate binding. Fragments containing the substrate-binding regions but lacking the PP1-binding motif trapped the phospho-substrate and caused accumulation of phosphorylated eIF2α in unstressed cells. Activity assays in cells showed that R15A325-674 and R15B340-713, encompassing the substrate-binding region and the PP1-binding region, exhibit wild-type activity. This work identifies the substrate-binding region in R15s, that functions as a phospho-substrate trapping mutant, thereby defining a key region of R15s for follow up studies.

High prevalence of syphilis in women, minors and precarious patients: a cross-sectional study in a Reunion Island sexually transmitted infection clinic, 2017-2020

BACKGROUND

Syphilis is a sexually transmitted infection (STI) with a global prevalence estimated at 0.5% in 2012. Syphilis has been on the rise among men who have sex with men (MSM) in high-income countries and remains at endemic levels in low- and middle-income countries. This trend, however, has not been observed in Reunion Island.

OBJECTIVES

To determine the prevalence, clinical characteristics and risk factors of syphilis in at-risk patients visiting the South Reunion STI clinic in Reunion Island.

METHODS

This monocentric cross-sectional study included all patients who visited our STI clinic between 2017 and 2020. Syphilis serology was performed on all included patients, and data were collected using a standardized self-administered questionnaire.

RESULTS

Over the 3-year study period, 2593 patients were enrolled. The prevalence of syphilis was 7.52% (n = 195, 95% CI, 6.50-8.65%) in the overall study population, 11.76% (n = 18, 95% CI, 6.97-18.59%) in minors (aged under 18 years) and 36.36% (n = 16, 95% CI, 21-59%) in pregnant women. The risk factors identified in multivariate analysis were being female [adjusted Prevalence Ratio (aPR) 1.85, 95% CI, 1.10-3.11], being MSM (aPR 2.87, 95% CI, 1.71-4.80), being aged under 18 years (aPR 3.54, 95% CI, 1.90-6.57), living in precarious conditions [aPR 3.12, 95% CI, 2.11-4.62] and being born in Reunion Island (aPR 2.43, 95% CI, 1.42-4.13). The clinical presentation was heterogeneous (plaques and papules, chancre, atypical ulcerations, multiple ulcerations, condyloma lata, etc.).

CONCLUSIONS

These findings suggest a high prevalence of syphilis in at-risk patients visiting our STI clinic. Unlike the situation in other high-income countries, the people most at risk of syphilis in Reunion Island are local-born residents, minors, women and precarious patients. This is a source of concern, especially given the risk of resurgence of congenital syphilis on the island.

Minors are the most affected by Chlamydia trachomatis in Reunion Island: A cross-sectional study, 2017-2018

OBJECTIVES

To determine the prevalence of Chlamydia trachomatis (CT) in the population screened at sexually transmitted infection (STI) clinics on Reunion Island and to identify risk factors for CT infection.

PATIENTS AND METHODS

This cross-sectional multicenter study was conducted in 2017-2018. Data were obtained from self-administered questionnaires and multiplex PCR tests.

RESULTS

The overall prevalence of CT in the screened population was 8.6% (95% CI 7.7-9.5%). The prevalence of urogenital CT was highest in women under 18 (13.2%, 95% CI 9.3-18.1%) and in men who have sex with men under 18 (13.3%, 95% CI 1.6-48.2%). Risk factors associated with CT infection in multivariate analysis were: female gender, being born in Reunion Island, having had a large number of sexual partners in the past year, and being co-infected with another STI.

CONCLUSIONS

The prevalence of CT in the screened population is higher in Reunion Island than in mainland France, especially in minors. Prevention campaigns targeting minors should be strengthened.

Protein Stability Buffers the Cost of Translation Attenuation following eIF2α Phosphorylation

Phosphorylation of the translation initiation factor eIF2α is a rapid and vital response to many forms of stress, including protein-misfolding stress in the endoplasmic reticulum (ER stress). It is believed to cause a general reduction in protein synthesis while enabling translation of few transcripts. Such a reduction of protein synthesis comes with the threat of depleting essential proteins, a risk thought to be mitigated by its transient nature. Here, we find that translation attenuation is not uniform, with cytosolic and mitochondrial ribosomal subunits being prominently downregulated. Translation attenuation of these targets persists after translation recovery. Surprisingly, this occurs without a measurable decrease in ribosomal proteins. Explaining this conundrum, translation attenuation preferentially targets long-lived proteins, a finding not only demonstrated by ribosomal proteins but also observed at a global level. This shows that protein stability buffers the cost of translational attenuation, establishing an evolutionary principle of cellular robustness.

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Translation attenuation following eIF2α phosphorylation is not uniform

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Low translation of downregulated targets persists after global translation recovery

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Translation attenuation following eIF2α phosphorylation favors long-lived proteins

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Protein stability buffers the cost of translational attenuation

[Prevalence and Risk Factors of Chlamydia Trachomatis Infection Among Women Consulting at the Sexually Transmitted Infection Centre in la Reunion: A Cross-Sectional Study]

Introduction

Chlamydia trachomatis (CT) infection is the commonest bacterial sexually transmitted infection (STI) in the world. Often asymptomatic, it can lead to significant complications in women. In France, since 2003, systematic screening for CT in STI center has been recommended for women aged less than 25 year. The main objective of this study was to determine CT prevalence in patients attending STI centers in Reunion Island. The second objective was to explore the determinants of this infection.

Method

A cross-sectional survey using an anonymous questionnaire was conducted among women attending STI center in two hospitals in western and southern Reunion Island during one year. All women who had performed a CT PCR, based on vaginal self-swabs, were included.

Results

Among the 620 patients tested, the prevalence of infection was 6.6% (95% CI [4.7-8.6]). By age group, the highest prevalence was between 12 and 17 years with 14.3% positive tests compared to 7.5% and 3.9% respectively in 18-24 and 25-67 year age group (p = 0.003). The risk factors for CT were a young age (p = 0.02), a first sexual intercourse between 11 and 14 years old (p = 0.01), lack of previous STI screening history (p = 0.02), and the following motives for seeking screening: "partner unfaithfulness" (p = 0.01) and "infected partner" (p = 0.02).

Conclusion

This study highlights the high prevalence of CT among Reunionese minors. A more systematic screening and a reinforcement of STI awareness among young people in Reunion Island seem to be essential.

Azithromycin resistance in Treponema pallidum in Reunion Island: A cross-sectional study

OBJECTIVE

Since the beginning of the 21st century, Reunion Island has experienced a syphilis epidemic. Infected patients are mostly heterosexual, with a high proportion of women, suggesting that congenital syphilis is present on the island. To determine whether azithromycin can be used for mass treatment of syphilis on Reunion Island, we assessed the prevalence of macrolide resistance in Treponema pallidum (TP).

METHODS

This monocentric cross-sectional study was conducted at the Reunion Island University Hospital. Samples were collected from lesions suggestive of primary or secondary syphilis. Samples positive for TP by multiplex polymerase chain reaction (PCR) were sent to the French National Reference Centre (NRC) for further analysis. Nested PCR-tpp47 was performed on these samples for detection of TP-DNA; 23s rRNA was amplified by PCR in confirmed positive samples. The Restriction Fragment Length Polymorphism (RFLP) technique was performed on samples with amplified 23s rRNA for detection of the A2058G mutation.

RESULTS

A total of 129 samples were collected from 119 patients. Of these, 18 tested positive for TP using multiplex PCR and were sent to the NRC. Fifteen (83.3%) of the 18 samples were confirmed positive by nested PCR-tpp47, and 23s rRNA was amplified in only 7 (38.9%) samples. Azithromycin resistance was detected in all TP strains with amplified 23s rRNA.

CONCLUSION

Amplification of 23s rRNA was successful in only 7 TP strains, all of which displayed resistance to macrolides. Keeping in mind the small sample size of our study, this suggests that azithromycin should not be used for mass treatment of syphilis in Reunion Island.

Prevalence of urogenital, anal, and pharyngeal infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium: a cross-sectional study in Reunion island

Background

Recommendations for sexually transmitted infection (STI) screening vary significantly across countries. This study evaluated the prevalence of urogenital and extragenital infections with Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Mycoplasma genitalium (MG) in patients visiting a French STI clinic in the Indian Ocean region to determine whether current STI screening practices should be updated.

Methods

This cross-sectional study examined all patients who visited the STI clinic between 2014 and 2015. Triplex polymerase chain reaction screening for CT, NG, and MG was performed on urine, vaginal, pharyngeal, and anal specimens (FTD Urethritis Basic Kit, Fast Track Diagnostics, Luxembourg).

Results

Of the 851 patients enrolled in the study, 367 were women (367/851, 43.2%) and 484 were men (484/851, 56.0%). Overall, 826 urogenital specimens (826/851, 97.1%), 606 pharyngeal specimens (606/851, 71.2%), and 127 anal specimens (127/851, 14.9%) were taken from enrolled patients. The prevalence of urogenital CT and MG was high in women ≤25 years (19/186, 10.21%; 5/186, 2.69%) and in men who have sex with women ≤30 years (16/212, 7.54%; 5/212, 2.36%). Among patients with urogenital CT infection, 13.7% (7/51) had urethritis. All patients with urogenital MG infection were asymptomatic. Men who have sex with men had a high prevalence of pharyngeal CT (2/45, 4.44%) and NG (3/44, 6.81%) and a high prevalence of anal CT (2/27, 7.41%), NG (2/27, 7.40%), and MG (1/27, 3.70%). After excluding patients with concomitant urogenital infection, extragenital infections with at least 1 of the 3 pathogens were found in 20 swabs (20/91, 21.9%) taken from 16 patients (16/81, 19.7%), all of them asymptomatic.

Conclusions

Routine multisite screening for CT, NG, and MG should be performed to mitigate the transmission of STIs in high-risk sexually active populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05801-9.

Potential benefit of manipulating protein quality control systems in neurodegenerative diseases

The deposition of proteins of abnormal conformation is one of the major hallmarks of the common neurodegenerative diseases including Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, frontotemporal dementia, and prion diseases. Protein quality control systems have evolved to protect cells and organisms against the harmful consequences of abnormally folded proteins that are constantly produced in small amounts. Mutations in rare inherited forms of neurodegenerative diseases have provided compelling evidence that failure of protein quality control systems can drive neurodegeneration. With extensive knowledge of these systems, and the notion that protein quality control may decline with age, many laboratories are now focussing on manipulating these evolutionarily optimized defence mechanisms to reduce the protein misfolding burden for therapeutic benefit.

Emergence of murine typhus in La Réunion, France, 2012-2017

OBJECTIVE

Murine typhus (MT) is an acute zoonosis caused by Rickettsia typhi, a flea-borne rickettsiosis. The first autochthonous case was reported in 2012. Once autochthonous transmission of Rickettsia typhi was proven, we performed a prospective study to describe and raise awareness of this often-misdiagnosed disease among physicians.

PATIENTS AND METHODS

We performed a prospective observational study of MT cases in La Réunion from 2012 to 2017. MT cases were defined as clinically compatible illnesses with a specific positive serology and/or PCR.

RESULTS

Sixty-one confirmed cases were collected. The main clinical features were prolonged fever (90%), asthenia (87%), and headaches (79%). The main biological abnormalities were elevated liver enzymes (84%) and thrombopenia (75%). Renal function was normal in 90% of cases; it was an important feature because leptospirosis is a frequent cause of acute renal failure. A seasonal factor was observed with 79% of cases reported in the warm season and most of them in the west and south of the island (i.e., the dry areas).

CONCLUSION

MT is an emerging disease in La Réunion, and local conditions could lead to an endemic situation. Cases of acute undifferentiated fever with headaches should guide to the diagnosis of MT especially in the warm season and dry areas. Leptospirosis is an alternative diagnosis, which differs from MT by its epidemiological characteristics and by the associated frequent renal dysfunction.