Dengue epidemic in a non-endemic zone of Bangladesh: clinical and laboratory profiles of 1 patients

26 Backgrounds: Approximately, half of the population in the world including tropical and sub- 27 tropical climates region is at risk of dengue. Being an endemic country, Bangladesh has 28 experienced the largest dengue epidemic in 2019. The present study aimed at evaluating the 29 clinical and laboratory profile of dengue patients in northern Bangladesh during the epidemic. 30 Methods: This cross-sectional study included 319 serologically confirmed dengue patients 31 admitted in Shaheed Ziaur Rahman Medical College Hospital in Bogra district. It is one of the 32 main tertiary care hospitals in northern Bangladesh. Data were collected from July to September 33 2019. Patients’ clinical and laboratory data were extracted from clinical records. Patients were 34 classified into two classes according to the WHO 2009 dengue classification such as (i) non- 35 severe dengue and (ii) severe dengue. Chi-square test and independent t-test were used in this 36 study. 37 Results: Of the 319 patients, 94.1% had non-severe dengue and the remaining 5.9% had severe 38 dengue (severe plasma leakage 68.4%, severe organ involvement 68.4%, and severe clinical 39 bleeding 10.5%). Most of the patients were suffering from primary dengue infection. The most 40 common clinical presentation was fever followed by headache and myalgia. Vomiting and 41 abdominal pain were the most prevalent warning signs. The common hematological findings on 42 admission were leukopenia (63.3%), thrombocytopenia (30.4%) and increased hematocrit 43 (26.6%). Raised serum ALT or AST was observed in 14.1% cases whereas raised serum 44 creatinine was observed in 6.6% cases. Signs of plasma leakage (pleural effusion, respiratory 45 distress, and ascites, rise of hematocrit >20% during hospital stay) and hepatic or renal 46 involvement (serum ALT >42UI/L or serum creatinine >1.2 mg/dL) on admission were mostly 47 associated with severe dengue. 3 Conclusion: The study provides clinical evidence on presentation as well as hematological and 49 biochemical profile of dengue patients in northern Bangladesh that should be implicated in 50 effective patient management.


Introduction 71
Dengue is an arboviral disease caused by Dengue virus (DENV) that transmitted to humans by 72 infected mosquitoes of the species Aedes aegypti and sometimes Aedes albopictus [1]. It has 73 become a significant public health concern worldwide in recent years especially for the South-74 East Asian, sub-Saharan African and Latin American countries [2]. Almost half of the world's 75 population, living in the tropical and subtropical climate of these regions is at risk of dengue 76 infection [3]. More than 390 million dengue virus infections occur worldwide every year causing 77 more than 20,000 deaths [4,5]. Bangladesh is situated in the dengue endemic zone of the South- Different serotypes can circulate simultaneously during an epidemic with a potential risk of 87 infecting a person as many as four times, once with each serotype. Subsequent infections with 88 different DENV serotypes increase disease severity [1]. Dengue infection can be clinically 89 presented with varying severity ranging from asymptomatic infection or self-limiting influenza-90 like illness to a potentially fatal dengue hemorrhagic fever or dengue shock syndrome [9]. It is 91 evidenced that all four serotypes were circulating in Bangladesh during different epidemics [10, 92 11] and during the current epidemic re-emergence of DEN-3 serotype was suspected, resulting in 93 a more severe form of dengue infection [12]. 94 All rights reserved. No reuse allowed without permission.
(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. ; https://doi.org/10.1101/2020.06.08.20126094 doi: medRxiv preprint Management of dengue cases during an epidemic is a major challenge for a limited resource 95 country like Bangladesh on duty, and who met the inclusion criteria were included in the study. The first dengue case of 117 the year was admitted to SZMC during the first week of June and continued to increase the 118 All rights reserved. No reuse allowed without permission.
(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. ; https://doi.org/10.1101/2020.06.08.20126094 doi: medRxiv preprint 6 number of cases up to last week of September. Last patient of our study was included on 119 September 24, and we observed for two more weeks for any new case. As there was no new case 120 during this period, the investigators decided to stop data collection. A total of 319 patients were 121 included in the study. 122 Inclusion and exclusion criteria: We followed two inclusion criteria such as (i) patients 123 presented with clinical criteria of dengue fever, defined as a history of acute fever with at least 124 two of the following symptoms: headache, retro-orbital or ocular pain, myalgia, arthralgia, rash, a (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. restlessness, liver enlargement >2 cm, increase in hematocrit (≥20%) concurrent with rapid 152 decrease in platelet count (≤100000/μL). Severe dengue was defined as having (i) severe plasma 153 leakage, defined as plasma leakage with shock or respiratory distress (respiratory rate ≥24 154 breaths/min with oxygen saturation <95 % in room air and/or requiring oxygen therapy), (ii) 155 severe clinical bleeding, defined as spontaneous bleeding from mucosal areas that necessitates a 156 blood transfusion, or (iii) severe organ involvement, defined as AST >1000 IU/L and/or ALT 157 >1000 IU/L, serum creatinine ≥2 times above baseline, myocarditis, and/or encephalitis [13]. 158 Thrombocytopenia, leukopenia, raised hematocrit, raised ALT, raised AST and raised creatinine 159 were defined as a platelet count of 100,000 platelets/μL or less, white blood cell count 5000 160 cells/μL, as >48% or ≥20% increase than baseline, as >42 IU/L, as >37 IU/L and as >1. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. ; https://doi.org/10.1101/2020.06.08.20126094 doi: medRxiv preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. Clinical presentations of dengue cases: The most common clinical feature on presentation was 194 fever (92.5%) followed by headache (72.7%) and myalgia (71.5%). Vomiting was the most 195 common warning sign (34.2%) followed by abdominal pain 95 (29.8%). Petechiae or rash was 196 the most common evidence of bleeding (15.7%) followed by melena (11.9%), sub-conjunctival 197 hemorrhage (8.8%) and gum bleeding (7.8%). The majority of symptoms at admission were 198 similar between patients with severe and non-severe dengue with some exceptions, which were 199 more frequently associated with severe dengue. These were not having fever, abdominal pain, 200 respiratory distress, hepatomegaly (> 2cm), ascites, pleural effusion, peripheral edema and shock 201 (Table 2). 202 (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. Hematological and biochemical parameters of dengue cases: It was observed that the most 206 common hematological finding on admission was leukopenia (< 5000) (63.3%) and 207 thrombocytopenia (< 100 000) (30.4%). Hematocrit > 48% were noted in 85 (26.6%) during total 208 hospital stay whereas >20% increase in hematocrit was observed in 74 (23.2%) patients. Alanine 209 aminotransferase (ALT) level >42 IU/L and aspartate aminotransferase (AST) level >37 IU/L 210 were observed in 40 (12.5%) cases and 16 (5.0%) cases respectively. Serum creatinine level >1.2 211 mg/dl was observed in 21 (6.6%) cases (Table 3). Most laboratory results among patients with 212 severe and non-severe dengue were similar with the exceptions of rise of hematocrit, ALT and 213 serum creatinine which were significantly higher among patients with severe dengue compared to 214 those with non-severe dengue. 215 Table 3: Hematological and biochemical parameters of dengue cases (n = 319) 216 All rights reserved. No reuse allowed without permission.
(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. All rights reserved. No reuse allowed without permission.
(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. 217

Discussion 218
The dengue epidemic has become a major public health threat for many South-East Asian 219 endemic countries. A number of outbreaks of dengue occurred in Bangladesh, mostly affecting 220 Dhaka, the capital city and the central region. Though the exact cause of being Dhaka an endemic 221 zone of dengue in Bangladesh, it is likely that the humid weather and more source of mosquito 222 breeding (stagnant clean water during rainy season) due to unplanned urbanization and poor 223 drainage system could make the city vulnerable for dengue infection. A nationwide sero-224 prevalence study reported much lower prevalence in the northern region of the country compared 225 to the central region and most of these cases were suspected to be referred from endemic zones 226 [21]. Despite the fact, during the 2019 epidemic a huge number of cases were reported from this 227 region [7] and travel history to endemic zone was not a significant risk factor of dengue infection 228 of these patients, as our study found. It is a matter of concern that dengue is not confined to the 229 reported endemic zone of the country; rather it has become a national health emergency. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. ; https://doi.org/10.1101/2020.06.08.20126094 doi: medRxiv preprint hematological and biochemical profile of dengue patients based on the updated case definition. 240 The present study was aimed at meeting the knowledge gap which would help to improve the 241 predictive and diagnostic process of dengue. 242 Clinical manifestations and laboratory profiles of our dengue patient cohort were quite similar to 243 the patients of previous dengue epidemics in Bangladesh [15,16,24,25]. Fever, headache, and 244 myalgia were the most common clinical presentations of our patients. In hematological 245 evaluation, leukopenia, thrombocytopenia, and raised hematocrit level were the most frequent 246 findings. Petechiae or skin rash was commonest bleeding manifestation among the present cohort 247 as evidenced in previous studies conducted in the endemic area [15,24], though the prevalence 248 was much lower here. However, severe dengue was mainly manifested as severe plasma leakage 249 and severe organ involvement in our study population rather than dengue hemorrhagic fever, 250 which was more prevalent in previous epidemics [24,25]. Severe plasma leakage was also a more 251 common manifestation of severe dengue during a recent epidemic in Singapore [26]. 252 Most of the patients of the present study were suffering from primary dengue while the ratio of 253 primary and secondary dengue was almost equal in previous epidemics that occurred in Dhaka 254 city [24]. The sero-prevalence of dengue was reported as much lower in our study region 255 compared to Dhaka city (21). Secondary infection was more likely to be associated with severe 256 dengue among our study population, consistent with findings of other studies [18,27,28]. 257 Fever, headache, retro-orbital pain and other constitutional symptoms were associated with non-258 sever dengue. The basic pathophysiology of this finding is that these non-specific symptoms of 259 viral febrile illness are mostly found in the febrile phase of dengue, whereas severe dengue is 260 usually manifested during the critical phase, when there is increased risk of plasma leakage and 261 shock [13,29]. For this phenomenon, patients, who were admitted during the critical phase of the 262 disease course developed severe dengue more frequently according to our finding, as evidenced 263 All rights reserved. No reuse allowed without permission.
(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. Most of the patients' suffering from severe dengue of our study cohort presented as severe plasma 278 leakage rather than severe hemorrhage, so thrombocytopenia was not significantly associated 279 with severe dengue. Our result suggests that severe organ involvement can be predicted from 280 early rise of biomarkers, especially serum ALT in case of liver involvement and serum creatinine 281 in case of renal involvement. Similar results were reported by others [18,26,[35][36][37]. 282 According to our findings, almost half of the admitted dengue patients in SZMCH had no 283 warning sign, which had made them vulnerable for developing severe dengue, as defined by the 284 WHO. There is a justifiable space for argument whether admitting these patients was appropriate 285 or not. As our study and previous ones suggested, warning signs like abdominal pain, 286 hepatomegaly as well as persistent vomiting were more likely associated with developing severe 287 disease, these clinical features should be taken into account when screening a dengue patient for 288 All rights reserved. No reuse allowed without permission.
(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. ; https://doi.org/10.1101/2020.06.08.20126094 doi: medRxiv preprint admission, especially in resource-poor settings like Bangladesh. Moreover, increasing hematocrit 289 >20% during hospital stay, raised liver enzyme and serum creatinine beyond upper margin of 290 normal value were associated with severe dengue. So, screening patients with these laboratory 291 parameters on first visit with periodic follow up keeping them on outdoor management may 292 reduce the hospital burden of those admitted patients for whom outdoor management was 293 potentially enough. 294 Although the present study was the first attempt to report dengue patient profile from a non-295 endemic region of the country, it has some limitations: (i) patients were recruited from a specific 296 geographic territory, which is not in the dengue-endemic zone of the country. So our data may not 297 be representative of dengue patients of the whole country; (ii) only hospitalized patients in the 298 study center (SZMCH) were included in this study and as a result, a number of non-severe 299 dengue patients, who were managed in outpatient settings and those who were treated in other 300 facilities as well as did not visit hospital due to mildness of symptoms or other causes were 301 missed, so the patients included in this study do not represent all the patients with dengue in this 302 region; (iii) we confirmed dengue based on serological test, RT-PCR to detect viral RNA and 303 serotyping of DENV was not done; (iv) hydration and volume expansion could have had an effect 304 on hematocrit that could potentially bias the data. Regardless of the depicted limitations, the 305 present study ultimately provides the baseline data on clinical, hematological and biochemical 306 profiles of dengue patients of the respective region of the country as well as generate evidence of 307 clinical and laboratory parameters to predict the development of severe dengue. 308 Conclusions: Management and prognosis of dengue are mostly based on clinical presentations as 309 well as laboratory findings like hematological and biochemical parameters. The present study 310 reported that fever, headache, and myalgia were the commonest presenting complaints of dengue 311 patients whereas vomiting and abdominal pain was the most prevalent warning signs. Severe 312 dengue was associated mostly with plasma leakage rather than hemorrhage and the rise of 313 All rights reserved. No reuse allowed without permission.
(which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted June 9, 2020. ; https://doi.org/10.1101/2020.06.08.20126094 doi: medRxiv preprint reviewing the manuscript. They would also like to thank Shahajada Farhan, Mahbuba Afrin, Md. 338 Ashikur Rahman, Md. Abdulla Al Faraby, Plaban Chandra Sarker and Md. Nahid Hasan for their 339 support in data collection. The authors would also like to express their sincere gratitude to all 340 study participants and the staff engaged in the study. 341