Clinical spectrum, disease course and management outcome of post-fever retinitis cases: experience from a tertiary eye institute in central India.

PURPOSE: To report a series of five cases with retinitis following episodes of febrile illness, its evaluation, management and outcome. METHOD: Retrospective, consecutive case series of five patients presenting with acute retinitis, following a febrile illness. RESULTS: The retinal lesions had a sudden onset with rapid evolution, preceded by a febrile episode within one month of presentation, in all cases. Extensive serology and PCR testing were non-contributory toward identifying the etiology and guiding therapy. Systemic corticosteroid therapy was effective in hastening the resolution of lesions. CONCLUSION: Post-fever retinitis appears to be a distinct clinical form of acute hemorrhagic non-necrotizing retinitis without a uniformly identifiable cause, and some evidence pointing toward a para-infectious etiology secondary to flu-like illnesses. With an unusual morphological presentation and annual seasonal patterns in the endemic areas, it is important to differentiate this entity, from other forms of infectious retinitis, before initiating corticosteroid therapy.

Clinical profile and response to steroids in post-fever retinitis: a nine-year experience from a referral institute in the rural hinterland of Central India.

PURPOSE: To describe the demographics, clinical features, and treatment outcomes with systemic steroids in eyes presenting with post-fever retinitis (PFR) from Central India. METHODS: Single-center, retrospective analysis of 147 eyes of 98 PFR cases between 2011 and 2019. RESULTS: Mean age of the study cohort was 33.46 ± 12.76 years, with 72 males and 26 females. The mean interval between the onset of fever and the diminution of vision was 21.10 ± 13.54 days (range 0-60 days). The number of PFR cases increased over the nine years with 89 cases (90.1%) presenting during winters. Unilateral involvement was seen in 49 cases, while 49 had bilateral involvement. Clinical characteristics included: multifocal retinitis (n = 122; 61.2%), hemorrhages (n = 132; 89.8%), disc edema (n = 57; 38.8%), anterior chamber reaction (n = 28; 19%), and vitritis (n = 103; 70.1%). Treatment included intravenous followed by oral steroids in 70 patients and oral steroids exclusively in 23; five patients denied treatment. The visual acuity improved from 1.09 ± 0.52 LogMAR to 0.29 ± 0.42 LogMAR (p < 0.05). CONCLUSION: There has been an increase in the prevalence of PFR cases over the last decade with clustering during the winters. Multifocal retinitis, retinal hemorrhages, and vitritis were the most common clinical findings in our series. The retinitis resolved with improvement in vision following steroid therapy in all eyes.

Role of multicolour imaging in post-fever retinitis involving posterior pole.

PURPOSE: To describe composite multicolour (MC) imaging features along with the monocoloured fundus reflectance images in active and resolving stages of post-fever retinitis (PFR). METHODS: Retrospective image analysis of cases of PFR who underwent dilated retinal clinical examination followed by optical coherence tomography and MC imaging. RESULTS: Twenty-five eyes of 18 patients diagnosed with PFR were included. There were 11 males and 7 females. Mean age of patients was 30.63 years. The retinitis lesion appeared bright white on MC image and white mainly on blue and green reflectance images during the active stages of PFR. The lesion appeared dull-grey to greyish white during the resolving stages and as dull-green in resolved cases. The active stages showed the presence of intraretinal/subretinal fluid which appeared as green colour on MC images and less green to normal during resolving stages. Hard exudates were seen as bright yellow- or orange-coloured spots on MC image during the resolving stages of the disease. CONCLUSION: The different stages of PFR show different colour on multicolour image and different reflectance patterns on individual colour reflectance channels. Hence, multimodal fundus imaging with different wavelength can be helpful for differentiation of activity in PFR.

Predictors of visual outcome in post-fever retinitis: a retrospective analysis.

PURPOSE: To identify the predictors of final visual outcome in cases with post-fever retinitis (PFR). METHODS: This is a retrospective study of cases with diagnosis of post-fever retinitis. Colour fundus photograph and optical coherence tomography (OCT) parameters at presentation and final visit were analysed. Various factors at presentation [age, systemic illness, best-corrected visual acuity (BCVA), area of retinitis and hard exudates, OCT parameters], at final visit (OCT parameters) and the treatment modalities used were correlated with BCVA at final visit. RESULTS: Twenty-four eyes of 16 patients with PFR were included in the study. Median BCVA at presentation was 6/60 and at final visit was 6/9. By multiple linear regression after adjusting for other variables, for every 1 unit increase in height of subretinal fluid (SRF) at fovea at presentation, the value of final BCVA decreased by 0.001 unit. For every 1 unit increase in extent of ellipsoid zone (EZ) loss and subfoveal deposit height, the value of final BCVA decreased by 0.0001 unit and 0.004 unit, respectively. The baseline OCT parameters that had negative correlation with final BCVA included central macular thickness (r: - 0.5182, p: 0.02), maximum SRF height (r: - 0.5539, p < 0.01) and SRF height at fovea (r: - 0.582, p < 0.01). The OCT parameters at final visit which had a negative correlation with final BCVA included disorganisation of retinal inner layers (DRIL) within 1000 microns from centre of fovea (r: - 0.6494, p < 0.01), height of subfoveal deposit (r: - 0.7627, p < 0.01), horizontal extent of subfoveal deposit (r: - 0.6695, p < 0.01) and extent of EZ loss (r: - 0.8216, p < 0.01). CONCLUSION: Height of SRF at presentation, extent of EZ loss and subfoveal deposit height at final visit were associated with poor final BCVA in PFR.

Vascular Changes in Eyes with Post-Fever Retinitis Pre and Post Treatment Demonstrated Using Optical Coherence Tomography Angiography.

PURPOSE: To document vascular changes in eyes with post-fever retinitis (PFR) pre and post treatment demonstrated using optical coherence tomography angiography (OCTA). METHODS: This is a retrospective observational case series wherein patients with PFR were retrospectively evaluated for changes in the retinal vasculature during the course of disease using OCTA. RESULTS: At presentation, OCTA revealed flow void areas in superficial and deep capillary plexus (SCP and DCP) corresponding to the areas of retinitis. Post treatment, OCTA showed a significant decrease in the flow void areas with the appearance of new capillary network in both SCP and DCP. The optical coherence tomography also demonstrated normalization of retinal architecture over time. It is speculated that the good visual outcome in PFR could be attributed to the normalization of retinal architecture and remodelling in retinal vasculature. CONCLUSION: OCTA being non-invasive can be used to understand and quantify the extent of vascular remodelling in PFR.

Post-fever Retinitis With a Positive Weil-Felix Test: A Study From a Tertiary Center in South India.

Background Post-fever retinitis (PFR) is reported two to six weeks after fever and affects one or both eyes. Rickettsial fever is one of the most common causes of PFR. This study aimed to report the clinical features and treatment outcomes of PFR cases with a positive Weil-Felix test. Methodology In this study, we collected demographic data, fever details, eye symptoms, ocular examination findings, optical coherence tomography (OCT) and fundus fluorescein angiography findings, laboratory findings, and length of follow-up of consecutive PFR cases with a positive Weil-Felix test. All cases were treated with oral doxycycline and prednisolone. Final best-corrected visual acuity (BCVA) and ocular examination findings were recorded. Visual field examination and follow-up OCT results were noted if available. Results A total of nine patients (eight males) with a mean age of 39.1 years with fever before ocular symptoms and positive Weil-Felix test were included. Six patients had bilateral disease. The mean initial and final BCVA in the affected eyes was 1.16 and 0.35 logMAR units, respectively (p < 0001). All 15 eyes had typical white retinitis patches and retinal hemorrhages which resolved after treatment. OCT showed hyperreflectivity and inner retinal disorganization over retinitis patches. White subretinal lines were noted in three patients and retinal nerve fiber bundle defect with corresponding visual field defect was seen in one eye. Conclusions In this study, PFR due to rickettsia infections has been reported from our region for the first time. Hence, eye specialists in the region should be aware of this entity.

Epidemic retinitis during pregnancy.

Purpose: To study the clinical presentation and treatment outcome of epidemic retinitis (ER) during pregnancy. Methods: This is a retrospective, observational chart review of pregnant patients diagnosed with ER from January 2014 to February 2023. Demographic details, month of pregnancy at the onset of ocular symptoms, history of present illness, clinical manifestations, and treatment outcomes were studied. Results: In 9 years, ER was seen in 86 females, of whom 12 (13.9%) were pregnant. Twenty-one eyes of those 12 patients were studied. Most of the patients presented in the sixth month of pregnancy (range: 5-9 months, mean: 6.3 months). Physicians diagnosed viral exanthematous fever in six, typhoid in three, and suspected rickettsia in one patient. Medical termination of pregnancy (MTP) was performed in two patients before presentation. Weil-Felix test was positive in five, Brucella in one, WIDAL in three, and coronavirus disease 2019 (COVID-19) IgG and dengue IgG in one patient each. Oral antibiotics were given in five patients (two post-medical termination of pregnancy [MTP]) for the retinitis. All except four received oral steroids. Mean presenting corrected distant visual acuity (n = 21) was 20/125 (range: 20/20-20/20,000), which improved to (n = 18) 20/30 (range: 20/20-20/240). Macular edema (n = 11) resolved in 33.18 days (range: 20-50 days), and retinitis (n = 13) resolved in 58 days (range: 30-110 days). Ocular and systemic examination of newborn was possible in two and the babies were normal. Conclusion: ER is seen commonly at the beginning of the third trimester. Lack of antibiotics may delay the resolution of retinitis. Ocular health needs to be assessed in larger series to conclude absence of retinal involvement in newborns.

Visual Fields in Epidemic Retinitis.

AIM: The aim of the study is to analyze visual fields defects (VFDs) in epidemic retinitis (ER). METHODS: Patients with ER and Humphrey's visual field (HFA) 30-2 performed after resolution were studied. VFD severity grading was performed. Patients treated with oral doxycycline (Group-A) versus doxycycline-steroids (group-B) were compared. RESULTS: Thirty-five eyes of 25 patients were studied. Nasal, inferior, temporal and central VFD were seen in 19 (54.2%), 13 (37.1%), 7 (20%) and 6 (17.1%) eyes, respectively. Grade 0, 1, 2 and 3 VFDs were seen in 4 (11.4%), 15 (42.8%), 12 (34.2%) and 4 (11.4%) eyes respectively. Seven eyes with ≥1 year of follow-up post-resolution also showed grade 0-3 scotomas. Mean severity of scotoma was grade 1.15 (Median: 1) and 1.42 (Median: 1.5) in groups A (n = 13) and B (n = 14), respectively (p = .637). CONCLUSION: ER can cause VFD persisting long after resolution. Treatment with oral doxycycline without steroids was non-inferior to combined treatment with respect to VFD.

Bilateral macular retinitis in patients with presumed rift valley fever from Sudan: A case series.

BACKGROUND: Epidemic retinitis occurs seasonally following febrile infections in endemic regions. Rift valley fever (RVF) is endemic to Sudan, with a recent outbreak starting in 2019. METHODS: Retrospective case series of 3 patients travelling from Sudan with post-febrile retinitis, and with a history and clinical picture suggestive of RVF retinitis. RESULTS: The three patients were adult males with underlying medical conditions and underwent fundus fluorescein angiography that confirmed bilateral retinitis and occlusive vasculitis involving the posterior pole. Optical coherence tomography showed distortion of the macular layers. Case 2 presented 1 month following febrile illness and had retinal thinning, with optical coherence tomography angiography showing marked reduction in vessel density. CONCLUSION: We present multimodal imaging data of three cases with presumed RVF retinitis from a recent outbreak in Sudan. The unavailability of standardized methods of testing for RVF, as is the case for most epidemic retinitis-causing pathogens, makes the diagnosis challenging.

Comments on 'Presumed Post-COVID Infection Retinitis - Clinical and Tomographic Features of Retinitis as a Post-COVID Syndrome'.

Characteristics and course of known seasonal diseases of pre-coronavirus disease (COVID-19) pandemic era may or may not change during the pandemic. Labelling COVID-19 as a novel etiology for those seasonal diseases or considering it as coinfection is debatable. Appropriate investigations are required to rule out previously known etiologies before correlating it with COVID-19. Epidemic retinitis (ER) or post fever retinitis is one such entity with seasonal variation. Multiple seropositivity for various organisms has been reported for ER during pre-pandemic era. This may significantly increase during the pandemic as the possibility of coinfection with COVID-19 is high. In the absence of gold-standard tests to exclude previously reported causes of ER, one should not undermine the possible coinfection before considering ER as post-COVID-19 syndrome. A study of incidence and pattern of seasonal variation of ER before and during the pandemic is needed before presumptively associating it with COVID-19.

Epidemic retinitis during the COVID-19 pandemic.

Purpose: To study the impact of the novel coronavirus disease-2019 (COVID-19) pandemic on incidence, seasonal variation, clinical presentation, and disease outcome of epidemic retinitis (ER) and to compare clinical outcomes with positive and negative COVID-19 serology. Methods: This is a retrospective, observational study conducted at a tertiary eye care hospital from August 2020 to June 2022. A graph of ER cases against the month of presentation was compared with the graph of the COVID-19 pandemic in the same region. Cases presented before COVID-19 vaccination, with positive COVID-19 serology (Group 1) were compared with cases with negative serology (Group 2). Results: One hundred and thirty-two cases of ER were seen. The least number of cases were seen during and immediately after the peak of the pandemic (May 2021-August 2021). COVID-19 serology was positive in 13 (22 eyes)/60 (21.6%) unvaccinated cases. Along with COVID-19, positive serology for other ER etiologies was seen in 5/13 cases (38.4%). All patients received oral doxycycline with/without steroids. Groups 1 and 2 included 22 and 21 eyes of 13 cases each. Macular edema resolved in 43.6 and 32 days in groups 1 and 2, respectively. Retinitis resolved at 1 month in both groups. Corrected distant visual acuity was 20/50 and 20/70 at the presentation, which improved to 20/20 and 20/25 in groups 1 and 2, respectively. Mean and median follow-up was 6 months and 4.5 months, respectively, in both groups. No complications or recurrences were seen. Conclusion: No significant impact of the COVID-19 pandemic on ER was observed.

Treatment Outcomes of Presumed Rickettsial Retinitis: Evidence from OCTA Based Quantitative Analysis.

AIM: To quantify retinal ischemia following presumed rickettsial retinitis (RR). To compare outcomes between initial treatment with Doxycycline (Group 1) versus steroids (Group 2). METHODS: Retrospective analysis of patients with presumed RR was done. ImageJ software was used to obtain %area of ischemia on swept-source optical coherence tomography angiography (SS-OCTA). RESULTS: Eleven eyes of 8 patients belonged to Group1 and 6 eyes of 3 patients belonged to Group 2. The BCVA improved from logMAR 0.8 ∓ 0.7 to logMAR 0.06 ∓ 0.08 (p < 0.002) and central foveal thickness (CFT) changed from 479µ ∓ 341.3µ to 163.5µ ∓ 20.5µ (p < 0.005) after a median of 5 weeks in Group 1. In Group 2, BCVA improved from logMAR 1.03 ∓ 0.05 to logMAR 0.23 ∓ 0.23 (p < 0.004) and CFT changed from 286.5µ ∓ 158.8µ to 177.5µ ∓ 25.9µ (>0.05) following a mean of 11 weeks. Mean %area of ischemia was 4.6 ∓ 1.5 in Group 1 and 13.9 ∓ 4.1 in Group 2. CONCLUSION: Analysis of flow deficit on SS-OCTA confirms that treatment with Doxycycline in presumed RR results in less ischemia and quicker recovery than initial treatment with steroids.

"Acute Bilateral Neuroretinitis and Panuveitis in A Patient with Coronavirus Disease 2019: A Case Report"- Few Comments.

During the Coronavirus Disease 2019 (COVID-19) pandemic, we have witnessed increase in number of reports of a known uveitic entity being associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Causal relation is yet to be proven for many reports. Perhaps, occurrence of a previously known region-specific endemic disease or closely resembling manifestations of a known disease in a non-endemic region during the COVID-19 pandemic might suggest a causal relationship. Epidemic retinitis (ER) or post fever retinitis is such condition with geographic variation. Occurrence of ER or ER-like manifestations in a non-endemic country during the pandemic should instigate further studies to consider SARS-CoV-2 as a causative organism.

Monitoring Weil-Felix test in epidemic retinitis.

Purpose: The objective was to study the positivity of the Weil-Felix test (WFT) in epidemic retinitis (ER) during the course of the disease. Methods: This is a retrospective, observational case series of patients diagnosed with ER and presented to a tertiary eye care hospital in south India. Patients with positive WFT at the presentation, and who underwent a follow-up WFT during or after the resolution of ER were studied from September 2019 to March 2022. Patient's demographics, timings of clinical presentation and resolution, and investigation details with a special focus on WFT positivity and its duration were noted. Results: Sixteen patients were studied. Patients presented after 5 weeks of the fever (range: 2-12 weeks, median: 4). After 1-2 months, WFT was still positive in eight patients (50%). Only in one patient titers increased after 1 month, while in others, the titers decreased (n = 11) or remained the same (n = 4). Repeated tests in those patients (n = 6) after 3-4 months turned negative. Resolution of ER was seen at 1.35 months (range: 1-3 months) after the presentation. The mean duration for WFT to turn negative was 2 months from the presentation (range: 1-4 months) or 3.2 months of the fever (range: 1.5-6 months). Conclusion: In contrast to the reported physician's observation of increasing titers of WFT after rickettsial fever, ophthalmologists may observe decreasing WFT titers in ER. The clinical resolution of ER may precede the normalization of WFT. Follow-up WFT titers should be studied in larger series in confirmed cases of rickettsial-ER to validate the affordable and readily available WFT in India.

Epidemic retinitis - Factors associated with poor visual outcomes.

PURPOSE: To identify factors other than macular edema and retinitis location responsible for poor visual outcomes in epidemic retinitis (ER). METHODS: A.retrospective, observational, comparative study. Eyes with corrected distant visual acuity (CDVA) 20/200 or worse at resolution formed Group A. Eyes with central macular thickness (CMT) 600 µm or worse and retinitis within 1500 µm to foveal center at the presentation, but improved to CDVA 20/200 or better at the resolution formed Group B. The patient's history, clinical presentation, imaging, and treatment outcomes were studied and the factors responsible for the final visual outcomes were compared in both groups. RESULTS: Groups A and B included 25 eyes each. The mean CDVA at the presentation was 20/400 (range: 20/125-20000) and 20/320 (range: 20/80-20000), and mean CMT at the presentation was 948.5 µm (range: 520-1553) and 912.2 µm (range: 615-1250) in Groups A and B, respectively. All eyes except 1 (Group A) had retinitis lesions within 1500 µm of foveal center. The mean CDVA at the resolution was 20/400 (range: 20/200-20/20000) and 20/40 (range: 20/20-20/80) in Groups A and B, respectively. Older age, male gender, diabetic status, delayed presentation, poor presenting CDVA, bilaterality, presence of keratic precipitates, disk pallor, retinal thinning, and subfoveal deposits had a statistically significant association, whereas the absence of skin rash, ellipsoid zone loss, negative WIDAL, Weil-Felix test, and delayed doxycycline therapy or use of steroids without doxycycline had a statistically insignificant association with poor visual outcomes. CONCLUSION: Apart from presenting CMT and location of retinitis, multiple demographic, clinical, and imaging factors can be implicated for poor visual outcomes.

Epidemic Retinitis with Positive or Negative Weil Felix Test - a Comparative Study and Outcome with Doxycycline.

PURPOSE: To compare clinical manifestations and disease outcomes in Epidemic Retinitis (ER) with positive or negative Weil Felix Test (WFT). METHODS: Retrospective, observational, comparative study. WFT positive or negative patients formed Group 1 and 2, respectively. Patients receiving oral doxycycline monotherapy formed subgroup A and B. Duration of resolution of macular edema and retinitis was compared. RESULTS: Novel finding of "ring retinitis" was observed equally in group 1 and 2. Complete resolution of macular edema took 41.3 days (range: 30-60 days) and 43.68 days (range: 20-105 days) (p = .668) and retinitis lesions resolved in 34.3 days (range: 14-65 days) and 34 days (range: 12-60 days) (p = .875) in group A and B, respectively. All (n = 14) eyes with retinitis within 1 disc diameter of fovea improved better than 20/80 except 1. CONCLUSION: No significant difference with respect to clinical, imaging findings and the treatment outcome was observed in WFT positive or negative cases.

Epidemic Retinitis with Macular Edema -Treatment Outcome with and without Steroids.

Purpose: To study treatment outcomes with and without oral corticosteroids in epidemic retinitis (ER).Method: A retrospective, observational study of 35 eyes of 29 patients diagnosed as ER. Days taken for resolution of macular edema and retinitis lesions were compared in patients treated with oral antibiotics (Group 1) and with corticosteroids-antibiotics combination (Group 2).Result: Eighteen eyes of 14 patients and 17 eyes of 15 patients formed Groups 1 and 2, respectively. At the presentation, mean best-corrected visual acuity (BCVA) was 40 and 44 letters and mean central macular thickness was 648 (±243) and 626 (±256) microns in Groups 1 and 2, respectively. Macular edema resolved in 30.83 and 31.94 days; retinitis lesions resolved in 36.71 and 41.41 days in Groups 1 and 2, respectively. BCVA improved to 74 and 77 letters in Groups 1 and 2, respectively.Conclusion: ER with macular edema can be well managed without corticosteroids.

Intraocular Viral Communities Associated With Post-fever Retinitis.

The virome of ocular fluids is naive. The results of this study highlight the virome in the vitreous fluid of the eye of individuals without any ocular infection and compare it with the virome of the vitreous fluid of individuals with retinitis. A total of 1,016,037 viral reads were generated from 25 vitreous fluid samples comprising control and post-fever retinitis (PFR) samples. The top 10 viral families in the vitreous fluids comprised of Myoviridae, Siphoviridae, Phycodnaviridae, Herpesviridae, Poxviridae, Iridoviridae, Podoviridae, Retroviridae, Baculoviridae, and Flaviviridae. Principal coordinate analysis and heat map analysis clearly discriminated the virome of the vitreous fluid of the controls from that of the PFR virome. The abundance of 10 viral genera increased significantly in the vitreous fluid virome of the post-fever retinitis group compared with the control group. Genus Lymphocryptovirus, comprising the human pathogen Epstein-Barr virus (EBV) that is also implicated in ocular infections was significantly abundant in eight out of the nine vitreous fluid viromes of post-fever retinitis group samples compared with the control viromes. Human viruses, such as Hepacivirus, Circovirus, and Kobuvirus, were also significantly increased in abundance in the vitreous fluid viromes of post-fever retinitis group samples compared with the control viromes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analysis and the network analysis depicted an increase in the immune response by the host in the post-fever retinitis group compared with the control group. All together, the results of the study indicate changes in the virome in the vitreous fluid of patients with the post-fever retinitis group compared to the control group.

Comparison of the Vitreous Fluid Bacterial Microbiomes between Individuals with Post Fever Retinitis and Healthy Controls.

Ocular microbiome research has gained momentum in the recent past and has provided new insights into health and disease conditions. However, studies on sight threatening intraocular inflammatory diseases have remained untouched. In the present study, we attempted to identify the bacterial microbiome associated with post fever retinitis using a metagenomic sequencing approach. For this purpose, bacterial ocular microbiomes were generated from vitreous samples collected from control individuals (VC, n = 19) and individuals with post fever retinitis (PFR, n = 9), and analysed. The results revealed 18 discriminative genera in the microbiomes of the two cohorts out of which 16 genera were enriched in VC and the remaining two in PFR group. These discriminative genera were inferred to have antimicrobial, anti-inflammatory, and probiotic function. Only two pathogenic bacteria were differentially abundant in 20% of the PFR samples. PCoA and heatmap analysis showed that the vitreous microbiomes of VC and PFR formed two distinct clusters indicating dysbiosis in the vitreous bacterial microbiomes. Functional assignments and network analysis also revealed that the vitreous bacterial microbiomes in the control group exhibited more evenness in the bacterial diversity and several bacteria had antimicrobial function compared to the PFR group.

Epidemic retinitis and community outbreaks.

PURPOSE: The objective of this study was to correlate seasonal variation of epidemic retinitis (ER) with concurrent community outbreaks. METHODS: This is a retrospective, observational, comparative study conducted in a tertiary care eye hospital in south India. Monthly variation in number of ER cases in comparison with reported community outbreaks by Integrated Disease Surveillance Program (IDSP) from 2009 to 2020 in the same region were studied. Month-wise graphs against number of patients were plotted for ER and for each community outbreak. RESULTS: ER was diagnosed in 163 patients. Diagnosis of presumed rickettsial ER was made in 48 cases (29.44%), chikungunya in 5, dengue in 3 and typhoid in 6 cases, while in other cases the etiological diagnosis remained uncertain (n = 101). Multiple positive serological tests were seen in 6 patients (Weil Felix Test (WFT) with WIDAL in 4 and chikungunya IgM with WFT in 2 patients). Relevant reported outbreaks by IDSP were: Pyrexia of unknown origin (PUO) (n = 5148), Chikungunya (n = 6577), Dengue (n = 7350), Measles (n = 1422), Mumps (n = 881), Rubella (n = 288), Malaria (n = 2262), Chicken Pox (n = 2385), Typhoid (n = 597), Kyasanur Forest Disease (n = 381), Scrub Typhus (n = 13), Typhus fever (n = 4), Japanese Encephalitis (n = 15). None of the outbreak graphs pattern was identical or similar to the graph of ER. Inverse relation of the graph of dengue outbreak with ER was observed. CONCLUSION: Inverse correlation between dengue and ER should be further studied for causation, which we believe may prove dengue as least common cause. Reporting of rickettsial outbreaks should be enhanced by undertaking statewide awareness and procurement of gold standard tests.